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BUS105 Exam Format Explained: What You Need to Know Before You Register

by Jerry

Understanding the BUS105 exam format before you register is crucial for building an effective study strategy and avoiding surprises on test day. The BUS105 exam evaluates your knowledge of business fundamentals, including management principles, marketing concepts, financial literacy, and organizational behavior. The test typically consists of multiple-choice questions designed to measure both theoretical understanding and practical application of business concepts. To prepare efficiently, familiarize yourself with the structure and types of questions you’ll face. Practicing with BUS105 Practice Questions from study4exam can give you a clear idea of what to expect. These resources replicate real exam conditions, allowing you to improve time management and accuracy while identifying areas that need more attention. More info visit this website: https://www.study4exam.com/saylor/free-bus105-questions Understanding the marking scheme, question difficulty, and key focus areas in advance ensures you go into the exam well-prepared and confident. With the right preparation strategy and quality practice materials, you can successfully master the BUS105 exam and take a significant step toward your academic or professional goals.

4 days, 4 hours

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[Patch v3 1/2] mm/huge_memory: add pmd folio to ds_queue in do_huge_zero_wp_pmd()

by Wei Yang

We add pmd folio into ds_queue on the first page fault in __do_huge_pmd_anonymous_page(), so that we can split it in case of memory pressure. This should be the same for a pmd folio during wp page fault. Commit 1ced09e0331f ("mm: allocate THP on hugezeropage wp-fault") miss to add it to ds_queue, which means system may not reclaim enough memory in case of memory pressure even the pmd folio is under used. Move deferred_split_folio() into map_anon_folio_pmd() to make the pmd folio installation consistent. Fixes: 1ced09e0331f ("mm: allocate THP on hugezeropage wp-fault") Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Lance Yang <lance.yang(a)linux.dev> Cc: Dev Jain <dev.jain(a)arm.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Lance Yang <lance.yang(a)linux.dev> Reviewed-by: Dev Jain <dev.jain(a)arm.com> Acked-by: Usama Arif <usamaarif642(a)gmail.com> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Cc: <stable(a)vger.kernel.org> --- v3: * rebase on latest mm-new * gather rb and acked-by v2: * add fix, cc stable and put description about the flow of current code * move deferred_split_folio() into map_anon_folio_pmd() --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 002922bb6e42..e86699306c5e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1317,6 +1317,7 @@ static void map_anon_folio_pmd(struct folio *folio, pmd_t *pmd, count_vm_event(THP_FAULT_ALLOC); count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_ALLOC); count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC); + deferred_split_folio(folio, false); } static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) @@ -1357,7 +1358,6 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); map_anon_folio_pmd(folio, vmf->pmd, vma, haddr); mm_inc_nr_ptes(vma->vm_mm); - deferred_split_folio(folio, false); spin_unlock(vmf->ptl); } -- 2.34.1

4 days, 5 hours

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[PATCH] media: mtk-mdp: Fix a reference leak bug in mtk_mdp_remove()

by Haoxiang Li

In mtk_mdp_probe(), vpu_get_plat_device() increases the reference count of the returned platform device. Add platform_device_put() to prevent reference leak. Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- drivers/media/platform/mediatek/mdp/mtk_mdp_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c index 80fdc6ff57e0..eb212ca1a083 100644 --- a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c +++ b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c @@ -242,6 +242,7 @@ static void mtk_mdp_remove(struct platform_device *pdev) pm_runtime_disable(&pdev->dev); vb2_dma_contig_clear_max_seg_size(&pdev->dev); + platform_device_put(mdp->vpu_dev); mtk_mdp_unregister_m2m_device(mdp); v4l2_device_unregister(&mdp->v4l2_dev); -- 2.25.1

4 days, 6 hours

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[PATCH v3] media: mtk-mdp: Fix error handling in probe function

by Haoxiang Li

Add mtk_mdp_unregister_m2m_device() on the error handling path to prevent resource leak. Add check for the return value of vpu_get_plat_device() to prevent null pointer dereference. And vpu_get_plat_device() increases the reference count of the returned platform device. Add platform_device_put() to prevent reference leak. Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- Changes in v3: - Modify the patch subject and description. - Patch v2 is a little bit verbose and trivial, so I changed the subject and moved the fixes of mtk_mdp_remove to a separate patch. Thanks, Nicolas! Changes in v2: - Add check for vpu_get_plat_device() - Add platform_device_put() in mtk_mdp_remove() - Add mtk_mdp_unregister_m2m_device() on the error handling path. - Modify the patch title and description. I think you are right. Thanks, CJ! --- .../media/platform/mediatek/mdp/mtk_mdp_core.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c index 80fdc6ff57e0..f78fa30f1864 100644 --- a/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c +++ b/drivers/media/platform/mediatek/mdp/mtk_mdp_core.c @@ -194,11 +194,17 @@ static int mtk_mdp_probe(struct platform_device *pdev) } mdp->vpu_dev = vpu_get_plat_device(pdev); + if (!mdp->vpu_dev) { + dev_err(&pdev->dev, "Failed to get vpu device\n"); + ret = -ENODEV; + goto err_vpu_get_dev; + } + ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp, VPU_RST_MDP); if (ret) { dev_err(&pdev->dev, "Failed to register reset handler\n"); - goto err_m2m_register; + goto err_reg_handler; } platform_set_drvdata(pdev, mdp); @@ -206,7 +212,7 @@ static int mtk_mdp_probe(struct platform_device *pdev) ret = vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32)); if (ret) { dev_err(&pdev->dev, "Failed to set vb2 dma mag seg size\n"); - goto err_m2m_register; + goto err_reg_handler; } pm_runtime_enable(dev); @@ -214,6 +220,12 @@ static int mtk_mdp_probe(struct platform_device *pdev) return 0; +err_reg_handler: + platform_device_put(mdp->vpu_dev); + +err_vpu_get_dev: + mtk_mdp_unregister_m2m_device(mdp); + err_m2m_register: v4l2_device_unregister(&mdp->v4l2_dev); -- 2.25.1

4 days, 6 hours

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[PATCH 0/1] Backport request: Fix reading issue on mcp2221

by Romain Sioen

Hi maintainers, Please consider backporting the following patches to the stable trees. These patches fix a significant reading issue with mcp2221 on i2c eeprom. This request is following the one I did previously to fix hid-mcp2221 in previous LTS versions. I have confirmed that the patches applie cleanly and build successfully against v6.12, v6.6, v6.1, v5.15 and v5.10 stable branches. Thanks, Romain Arnaud Lecomte (1): hid: fix I2C read buffer overflow in raw_event() for mcp2221 drivers/hid/hid-mcp2221.c | 4 ++++ 1 file changed, 4 insertions(+) -- 2.48.1

4 days, 6 hours

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[PATCH v3] drm/nouveau: Fix refcount leak in nouveau_connector_detect

by Shuhao Fu

A possible inconsistent refcount update has been identified in function `nouveau_connector_detect`, which may cause a resource leak. After calling `pm_runtime_get_*(dev->dev)`, the usage counter of `dev->dev` gets increased. In case function `nvif_outp_edid_get` returns negative, function `nouveau_connector_detect` returns without decreasing the usage counter of `dev->dev`, causing a refcount inconsistency. Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/450 Fixes: 0cd7e0718139 ("drm/nouveau/disp: add output method to fetch edid") Signed-off-by: Shuhao Fu <sfual(a)cse.ust.hk> Cc: stable(a)vger.kernel.org Change in v3: - Cc stable Change in v2: - Add "Fixes" and "Cc" tags --- drivers/gpu/drm/nouveau/nouveau_connector.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 63621b151..45caccade 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -600,8 +600,10 @@ nouveau_connector_detect(struct drm_connector *connector, bool force) new_edid = drm_get_edid(connector, nv_encoder->i2c); } else { ret = nvif_outp_edid_get(&nv_encoder->outp, (u8 **)&new_edid); - if (ret < 0) - return connector_status_disconnected; + if (ret < 0) { + conn_status = connector_status_disconnected; + goto out; + } } nouveau_connector_set_edid(nv_connector, new_edid); -- 2.39.5

4 days, 11 hours

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+ mm-damon-sysfs-dealloc-commit-test-ctx-always.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/damon/sysfs: dealloc commit test ctx always has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-sysfs-dealloc-commit-test-ctx-always.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: SeongJae Park <sj(a)kernel.org> Subject: mm/damon/sysfs: dealloc commit test ctx always Date: Fri, 3 Oct 2025 13:14:55 -0700 The damon_ctx for testing online DAMON parameters commit inputs is deallocated only when the test fails. This means memory is leaked for every successful online DAMON parameters commit. Fix the leak by always deallocating it. Link: https://lkml.kernel.org/r/20251003201455.41448-3-sj@kernel.org Fixes: 4c9ea539ad59 ("mm/damon/sysfs: validate user inputs from damon_sysfs_commit_input()") Signed-off-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> [6.15+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/sysfs.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/mm/damon/sysfs.c~mm-damon-sysfs-dealloc-commit-test-ctx-always +++ a/mm/damon/sysfs.c @@ -1476,12 +1476,11 @@ static int damon_sysfs_commit_input(void if (!test_ctx) return -ENOMEM; err = damon_commit_ctx(test_ctx, param_ctx); - if (err) { - damon_destroy_ctx(test_ctx); + if (err) goto out; - } err = damon_commit_ctx(kdamond->damon_ctx, param_ctx); out: + damon_destroy_ctx(test_ctx); damon_destroy_ctx(param_ctx); return err; } _ Patches currently in -mm which might be from sj(a)kernel.org are mm-damon-sysfs-catch-commit-test-ctx-alloc-failure.patch mm-damon-sysfs-dealloc-commit-test-ctx-always.patch mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch mm-zswap-fix-typos-s-zwap-zswap.patch mm-zswap-s-red-black-tree-xarray.patch docs-admin-guide-mm-zswap-s-red-black-tree-xarray.patch

4 days, 14 hours

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+ mm-damon-sysfs-catch-commit-test-ctx-alloc-failure.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/damon/sysfs: catch commit test ctx alloc failure has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-sysfs-catch-commit-test-ctx-alloc-failure.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: SeongJae Park <sj(a)kernel.org> Subject: mm/damon/sysfs: catch commit test ctx alloc failure Date: Fri, 3 Oct 2025 13:14:54 -0700 The damon_ctx for testing online DAMON parameters commit inputs is used without its allocation failure check. This could result in an invalid memory access. Fix it by directly returning an error when the allocation failed. Link: https://lkml.kernel.org/r/20251003201455.41448-2-sj@kernel.org Fixes: 4c9ea539ad59 ("mm/damon/sysfs: validate user inputs from damon_sysfs_commit_input()") Signed-off-by: SeongJae Park <sj(a)kernel.org> Cc: <stable(a)vger.kernel.org> [6.15+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/sysfs.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/damon/sysfs.c~mm-damon-sysfs-catch-commit-test-ctx-alloc-failure +++ a/mm/damon/sysfs.c @@ -1473,6 +1473,8 @@ static int damon_sysfs_commit_input(void if (IS_ERR(param_ctx)) return PTR_ERR(param_ctx); test_ctx = damon_new_ctx(); + if (!test_ctx) + return -ENOMEM; err = damon_commit_ctx(test_ctx, param_ctx); if (err) { damon_destroy_ctx(test_ctx); _ Patches currently in -mm which might be from sj(a)kernel.org are mm-damon-sysfs-catch-commit-test-ctx-alloc-failure.patch mm-damon-sysfs-dealloc-commit-test-ctx-always.patch mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch mm-zswap-fix-typos-s-zwap-zswap.patch mm-zswap-s-red-black-tree-xarray.patch docs-admin-guide-mm-zswap-s-red-black-tree-xarray.patch

4 days, 14 hours

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+ mm-swap-do-not-perform-synchronous-discard-during-allocation.patch added to mm-new branch

by Andrew Morton

The patch titled Subject: mm, swap: do not perform synchronous discard during allocation has been added to the -mm mm-new branch. Its filename is mm-swap-do-not-perform-synchronous-discard-during-allocation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Kairui Song <kasong(a)tencent.com> Subject: mm, swap: do not perform synchronous discard during allocation Date: Tue, 07 Oct 2025 04:02:33 +0800 Patch series "mm, swap: misc cleanup and bugfix". A few cleanups and a bugfix that are either suitable after the swap table phase I or found during code review. Patch 1 is a bugfix and needs to be included in the stable branch, the rest have no behavior change. This patch (of 4): Since commit 1b7e90020eb77 ("mm, swap: use percpu cluster as allocation fast path"), swap allocation is protected by a local lock, which means we can't do any sleeping calls during allocation. However, the discard routine is not taken well care of. When the swap allocator failed to find any usable cluster, it would look at the pending discard cluster and try to issue some blocking discards. It may not necessarily sleep, but the cond_resched at the bio layer indicates this is wrong when combined with a local lock. And the bio GFP flag used for discard bio is also wrong (not atomic). It's arguable whether this synchronous discard is helpful at all. In most cases, the async discard is good enough. And the swap allocator is doing very differently at organizing the clusters since the recent change, so it is very rare to see discard clusters piling up. So far, no issues have been observed or reported with typical SSD setups under months of high pressure. This issue was found during my code review. But by hacking the kernel a bit: adding a mdelay(100) in the async discard path, this issue will be observable with WARNING triggered by the wrong GFP and cond_resched in the bio layer. So let's fix this issue in a safe way: remove the synchronous discard in the swap allocation path. And when order 0 is failing with all cluster list drained on all swap devices, try to do a discard following the swap device priority list. If any discards released some cluster, try the allocation again. This way, we can still avoid OOM due to swap failure if the hardware is very slow and memory pressure is extremely high. Link: https://lkml.kernel.org/r/20251007-swap-clean-after-swap-table-p1-v1-0-7486… Link: https://lkml.kernel.org/r/20251007-swap-clean-after-swap-table-p1-v1-1-7486… Fixes: 1b7e90020eb77 ("mm, swap: use percpu cluster as allocation fast path") Signed-off-by: Kairui Song <kasong(a)tencent.com> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Baoquan He <bhe(a)redhat.com> Cc: Barry Song <baohua(a)kernel.org> Cc: Chris Li <chrisl(a)kernel.org> Cc: David Hildenbrand <david(a)redhat.com> Cc: "Huang, Ying" <ying.huang(a)linux.alibaba.com> Cc: Kemeng Shi <shikemeng(a)huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Nhat Pham <nphamcs(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/swapfile.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) --- a/mm/swapfile.c~mm-swap-do-not-perform-synchronous-discard-during-allocation +++ a/mm/swapfile.c @@ -1101,13 +1101,6 @@ new_cluster: goto done; } - /* - * We don't have free cluster but have some clusters in discarding, - * do discard now and reclaim them. - */ - if ((si->flags & SWP_PAGE_DISCARD) && swap_do_scheduled_discard(si)) - goto new_cluster; - if (order) goto done; @@ -1394,6 +1387,33 @@ start_over: return false; } +/* + * Discard pending clusters in a synchronized way when under high pressure. + * Return: true if any cluster is discarded. + */ +static bool swap_sync_discard(void) +{ + bool ret = false; + int nid = numa_node_id(); + struct swap_info_struct *si, *next; + + spin_lock(&swap_avail_lock); + plist_for_each_entry_safe(si, next, &swap_avail_heads[nid], avail_lists[nid]) { + spin_unlock(&swap_avail_lock); + if (get_swap_device_info(si)) { + if (si->flags & SWP_PAGE_DISCARD) + ret = swap_do_scheduled_discard(si); + put_swap_device(si); + } + if (ret) + break; + spin_lock(&swap_avail_lock); + } + spin_unlock(&swap_avail_lock); + + return ret; +} + /** * folio_alloc_swap - allocate swap space for a folio * @folio: folio we want to move to swap @@ -1432,11 +1452,17 @@ int folio_alloc_swap(struct folio *folio } } +again: local_lock(&percpu_swap_cluster.lock); if (!swap_alloc_fast(&entry, order)) swap_alloc_slow(&entry, order); local_unlock(&percpu_swap_cluster.lock); + if (unlikely(!order && !entry.val)) { + if (swap_sync_discard()) + goto again; + } + /* Need to call this even if allocation failed, for MEMCG_SWAP_FAIL. */ if (mem_cgroup_try_charge_swap(folio, entry)) goto out_free; _ Patches currently in -mm which might be from kasong(a)tencent.com are mm-swap-do-not-perform-synchronous-discard-during-allocation.patch mm-swap-rename-helper-for-setup-bad-slots.patch mm-swap-cleanup-swap-entry-allocation-parameter.patch mm-migrate-swap-drop-usage-of-folio_index.patch

4 days, 16 hours

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+ mm-ksm-fix-exec-fork-inheritance-support-for-prctl.patch added to mm-new branch

by Andrew Morton

The patch titled Subject: mm/ksm: fix exec/fork inheritance support for prctl has been added to the -mm mm-new branch. Its filename is mm-ksm-fix-exec-fork-inheritance-support-for-prctl.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: xu xin <xu.xin16(a)zte.com.cn> Subject: mm/ksm: fix exec/fork inheritance support for prctl Date: Tue, 7 Oct 2025 18:28:21 +0800 (CST) Patch series "ksm: fix exec/fork inheritance", v2. This series fixes exec/fork inheritance. See the detailed description of the issue below. This patch (of 2): Background ========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") introduced MMF_VM_MERGE_ANY for mm->flags, and allowed user to set it by prctl() so that the process's VMAs are forcibly scanned by ksmd. Subsequently, the 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") supported inheriting the MMF_VM_MERGE_ANY flag when a task calls execve(). Finally, commit 3a9e567ca45fb ("mm/ksm: fix ksm exec support for prctl") fixed the issue that ksmd doesn't scan the mm_struct with MMF_VM_MERGE_ANY by adding the mm_slot to ksm_mm_head in __bprm_mm_init(). Problem ======= In some extreme scenarios, however, this inheritance of MMF_VM_MERGE_ANY during exec/fork can fail. For example, when the scanning frequency of ksmd is tuned extremely high, a process carrying MMF_VM_MERGE_ANY may still fail to pass it to the newly exec'd process. This happens because ksm_execve() is executed too early in the do_execve flow (prematurely adding the new mm_struct to the ksm_mm_slot list). As a result, before do_execve completes, ksmd may have already performed a scan and found that this new mm_struct has no VM_MERGEABLE VMAs, thus clearing its MMF_VM_MERGE_ANY flag. Consequently, when the new program executes, the flag MMF_VM_MERGE_ANY inheritance missed. Root reason =========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") clear the flag MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs. Solution ======== Firstly, Don't clear MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs, because perhaps their mm_struct has just been added to ksm_mm_slot list, and its process has not yet officially started running or has not yet performed mmap/brk to allocate anonymous VMAS. Secondly, recheck MMF_VM_MERGEABLE again if a process takes MMF_VM_MERGE_ANY, and create a mm_slot and join it into ksm_scan_list again. Link: https://lkml.kernel.org/r/20251007182504440BJgK8VXRHh8TD7IGSUIY4@zte.com.cn Link: https://lkml.kernel.org/r/20251007182821572h_SoFqYZXEP1mvWI4n9VL@zte.com.cn Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") Fixes: d7597f59d1d3 ("mm: add new api to enable ksm per process") Signed-off-by: xu xin <xu.xin16(a)zte.com.cn> Cc: Stefan Roesch <shr(a)devkernel.io> Cc: David Hildenbrand <david(a)redhat.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Wang Yaxin <wang.yaxin(a)zte.com.cn> Cc: Yang Yang <yang.yang29(a)zte.com.cn> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/ksm.h | 4 ++-- mm/ksm.c | 20 +++++++++++++++++--- 2 files changed, 19 insertions(+), 5 deletions(-) --- a/include/linux/ksm.h~mm-ksm-fix-exec-fork-inheritance-support-for-prctl +++ a/include/linux/ksm.h @@ -17,7 +17,7 @@ #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags); -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags); int ksm_enable_merge_any(struct mm_struct *mm); int ksm_disable_merge_any(struct mm_struct *mm); @@ -103,7 +103,7 @@ bool ksm_process_mergeable(struct mm_str #else /* !CONFIG_KSM */ -static inline vm_flags_t ksm_vma_flags(const struct mm_struct *mm, +static inline vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { return vm_flags; --- a/mm/ksm.c~mm-ksm-fix-exec-fork-inheritance-support-for-prctl +++ a/mm/ksm.c @@ -2617,8 +2617,14 @@ no_vmas: spin_unlock(&ksm_mmlist_lock); mm_slot_free(mm_slot_cache, mm_slot); + /* + * Only clear MMF_VM_MERGEABLE. We must not clear + * MMF_VM_MERGE_ANY, because for those MMF_VM_MERGE_ANY process, + * perhaps their mm_struct has just been added to ksm_mm_slot + * list, and its process has not yet officially started running + * or has not yet performed mmap/brk to allocate anonymous VMAS. + */ mm_flags_clear(MMF_VM_MERGEABLE, mm); - mm_flags_clear(MMF_VM_MERGE_ANY, mm); mmap_read_unlock(mm); mmdrop(mm); } else { @@ -2736,12 +2742,20 @@ static int __ksm_del_vma(struct vm_area_ * * Returns: @vm_flags possibly updated to mark mergeable. */ -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { if (mm_flags_test(MMF_VM_MERGE_ANY, mm) && - __ksm_should_add_vma(file, vm_flags)) + __ksm_should_add_vma(file, vm_flags)) { vm_flags |= VM_MERGEABLE; + /* + * Generally, the flags here always include MMF_VM_MERGEABLE. + * However, in rare cases, this flag may be cleared by ksmd who + * scans a cycle without finding any mergeable vma. + */ + if (unlikely(!mm_flags_test(MMF_VM_MERGEABLE, mm))) + __ksm_enter(mm); + } return vm_flags; } _ Patches currently in -mm which might be from xu.xin16(a)zte.com.cn are mm-ksm-fix-exec-fork-inheritance-support-for-prctl.patch selftests-update-ksm-inheritation-tests-for-prctl-fork-exec.patch

4 days, 17 hours

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[merged mm-hotfixes-stable] mm-hugetlb-avoid-soft-lockup-when-mprotect-to-large-memory-area.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm: hugetlb: avoid soft lockup when mprotect to large memory area has been removed from the -mm tree. Its filename was mm-hugetlb-avoid-soft-lockup-when-mprotect-to-large-memory-area.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Yang Shi <yang(a)os.amperecomputing.com> Subject: mm: hugetlb: avoid soft lockup when mprotect to large memory area Date: Mon, 29 Sep 2025 13:24:02 -0700 When calling mprotect() to a large hugetlb memory area in our customer's workload (~300GB hugetlb memory), soft lockup was observed: watchdog: BUG: soft lockup - CPU#98 stuck for 23s! [t2_new_sysv:126916] CPU: 98 PID: 126916 Comm: t2_new_sysv Kdump: loaded Not tainted 6.17-rc7 Hardware name: GIGACOMPUTING R2A3-T40-AAV1/Jefferson CIO, BIOS 5.4.4.1 07/15/2025 pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc��: mte_clear_page_tags+0x14/0x24 lr��: mte_sync_tags+0x1c0/0x240 sp��: ffff80003150bb80 x29: ffff80003150bb80 x28: ffff00739e9705a8 x27: 0000ffd2d6a00000 x26: 0000ff8e4bc00000 x25: 00e80046cde00f45 x24: 0000000000022458 x23: 0000000000000000 x22: 0000000000000004 x21: 000000011b380000 x20: ffff000000000000 x19: 000000011b379f40 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffc875e0aa5e2c x8��: 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5��: fffffc01ce7a5c00 x4 : 00000000046cde00 x3 : fffffc0000000000 x2��: 0000000000000004 x1 : 0000000000000040 x0 : ffff0046cde7c000 Call trace: ��mte_clear_page_tags+0x14/0x24 ��set_huge_pte_at+0x25c/0x280 ��hugetlb_change_protection+0x220/0x430 ��change_protection+0x5c/0x8c ��mprotect_fixup+0x10c/0x294 ��do_mprotect_pkey.constprop.0+0x2e0/0x3d4 ��__arm64_sys_mprotect+0x24/0x44 ��invoke_syscall+0x50/0x160 ��el0_svc_common+0x48/0x144 ��do_el0_svc+0x30/0xe0 ��el0_svc+0x30/0xf0 ��el0t_64_sync_handler+0xc4/0x148 ��el0t_64_sync+0x1a4/0x1a8 Soft lockup is not triggered with THP or base page because there is cond_resched() called for each PMD size. Although the soft lockup was triggered by MTE, it should be not MTE specific. The other processing which takes long time in the loop may trigger soft lockup too. So add cond_resched() for hugetlb to avoid soft lockup. Link: https://lkml.kernel.org/r/20250929202402.1663290-1-yang@os.amperecomputing.… Fixes: 8f860591ffb2 ("[PATCH] Enable mprotect on huge pages") Signed-off-by: Yang Shi <yang(a)os.amperecomputing.com> Tested-by: Carl Worth <carl(a)os.amperecomputing.com> Reviewed-by: Christoph Lameter (Ampere) <cl(a)gentwo.org> Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com> Acked-by: David Hildenbrand <david(a)redhat.com> Acked-by: Oscar Salvador <osalvador(a)suse.de> Reviewed-by: Anshuman Khandual <anshuman.khandual(a)arm.com> Reviewed-by: Dev Jain <dev.jain(a)arm.com> Cc: Muchun Song <muchun.song(a)linux.dev> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/hugetlb.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/hugetlb.c~mm-hugetlb-avoid-soft-lockup-when-mprotect-to-large-memory-area +++ a/mm/hugetlb.c @@ -7222,6 +7222,8 @@ long hugetlb_change_protection(struct vm psize); } spin_unlock(ptl); + + cond_resched(); } /* * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare _ Patches currently in -mm which might be from yang(a)os.amperecomputing.com are

4 days, 18 hours

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[merged mm-hotfixes-stable] fsnotify-pass-correct-offset-to-fsnotify_mmap_perm.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: fsnotify: pass correct offset to fsnotify_mmap_perm() has been removed from the -mm tree. Its filename was fsnotify-pass-correct-offset-to-fsnotify_mmap_perm.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ryan Roberts <ryan.roberts(a)arm.com> Subject: fsnotify: pass correct offset to fsnotify_mmap_perm() Date: Fri, 3 Oct 2025 16:52:36 +0100 fsnotify_mmap_perm() requires a byte offset for the file about to be mmap'ed. But it is called from vm_mmap_pgoff(), which has a page offset. Previously the conversion was done incorrectly so let's fix it, being careful not to overflow on 32-bit platforms. Discovered during code review. Link: https://lkml.kernel.org/r/20251003155238.2147410-1-ryan.roberts@arm.com Fixes: 066e053fe208 ("fsnotify: add pre-content hooks on mmap()") Signed-off-by: Ryan Roberts <ryan.roberts(a)arm.com> Reviewed-by: Kiryl Shutsemau <kas(a)kernel.org> Cc: Amir Goldstein <amir73il(a)gmail.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/util.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/util.c~fsnotify-pass-correct-offset-to-fsnotify_mmap_perm +++ a/mm/util.c @@ -566,6 +566,7 @@ unsigned long vm_mmap_pgoff(struct file unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff) { + loff_t off = (loff_t)pgoff << PAGE_SHIFT; unsigned long ret; struct mm_struct *mm = current->mm; unsigned long populate; @@ -573,7 +574,7 @@ unsigned long vm_mmap_pgoff(struct file ret = security_mmap_file(file, prot, flag); if (!ret) - ret = fsnotify_mmap_perm(file, prot, pgoff >> PAGE_SHIFT, len); + ret = fsnotify_mmap_perm(file, prot, off, len); if (!ret) { if (mmap_write_lock_killable(mm)) return -EINTR; _ Patches currently in -mm which might be from ryan.roberts(a)arm.com are

4 days, 18 hours

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[merged mm-hotfixes-stable] mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/ksm: fix flag-dropping behavior in ksm_madvise has been removed from the -mm tree. Its filename was mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Jakub Acs <acsjakub(a)amazon.de> Subject: mm/ksm: fix flag-dropping behavior in ksm_madvise Date: Wed, 1 Oct 2025 09:03:52 +0000 syzkaller discovered the following crash: (kernel BUG) [ 44.607039] ------------[ cut here ]------------ [ 44.607422] kernel BUG at mm/userfaultfd.c:2067! [ 44.608148] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 44.608814] CPU: 1 UID: 0 PID: 2475 Comm: reproducer Not tainted 6.16.0-rc6 #1 PREEMPT(none) [ 44.609635] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 44.610695] RIP: 0010:userfaultfd_release_all+0x3a8/0x460 <snip other registers, drop unreliable trace> [ 44.617726] Call Trace: [ 44.617926] <TASK> [ 44.619284] userfaultfd_release+0xef/0x1b0 [ 44.620976] __fput+0x3f9/0xb60 [ 44.621240] fput_close_sync+0x110/0x210 [ 44.622222] __x64_sys_close+0x8f/0x120 [ 44.622530] do_syscall_64+0x5b/0x2f0 [ 44.622840] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 44.623244] RIP: 0033:0x7f365bb3f227 Kernel panics because it detects UFFD inconsistency during userfaultfd_release_all(). Specifically, a VMA which has a valid pointer to vma->vm_userfaultfd_ctx, but no UFFD flags in vma->vm_flags. The inconsistency is caused in ksm_madvise(): when user calls madvise() with MADV_UNMEARGEABLE on a VMA that is registered for UFFD in MINOR mode, it accidentally clears all flags stored in the upper 32 bits of vma->vm_flags. Assuming x86_64 kernel build, unsigned long is 64-bit and unsigned int and int are 32-bit wide. This setup causes the following mishap during the &= ~VM_MERGEABLE assignment. VM_MERGEABLE is a 32-bit constant of type unsigned int, 0x8000'0000. After ~ is applied, it becomes 0x7fff'ffff unsigned int, which is then promoted to unsigned long before the & operation. This promotion fills upper 32 bits with leading 0s, as we're doing unsigned conversion (and even for a signed conversion, this wouldn't help as the leading bit is 0). & operation thus ends up AND-ing vm_flags with 0x0000'0000'7fff'ffff instead of intended 0xffff'ffff'7fff'ffff and hence accidentally clears the upper 32-bits of its value. Fix it by changing `VM_MERGEABLE` constant to unsigned long, using the BIT() macro. Note: other VM_* flags are not affected: This only happens to the VM_MERGEABLE flag, as the other VM_* flags are all constants of type int and after ~ operation, they end up with leading 1 and are thus converted to unsigned long with leading 1s. Note 2: After commit 31defc3b01d9 ("userfaultfd: remove (VM_)BUG_ON()s"), this is no longer a kernel BUG, but a WARNING at the same place: [ 45.595973] WARNING: CPU: 1 PID: 2474 at mm/userfaultfd.c:2067 but the root-cause (flag-drop) remains the same. [akpm(a)linux-foundation.org: rust bindgen wasn't able to handle BIT(), from Miguel] Link: https://lore.kernel.org/oe-kbuild-all/202510030449.VfSaAjvd-lkp@intel.com/ Link: https://lkml.kernel.org/r/20251001090353.57523-2-acsjakub@amazon.de Fixes: 7677f7fd8be7 ("userfaultfd: add minor fault registration mode") Signed-off-by: Jakub Acs <acsjakub(a)amazon.de> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis(a)gmail.com> Acked-by: David Hildenbrand <david(a)redhat.com> Acked-by: SeongJae Park <sj(a)kernel.org> Tested-by: Alice Ryhl <aliceryhl(a)google.com> Tested-by: Miguel Ojeda <miguel.ojeda.sandonis(a)gmail.com> Cc: Xu Xin <xu.xin16(a)zte.com.cn> Cc: Chengming Zhou <chengming.zhou(a)linux.dev> Cc: Peter Xu <peterx(a)redhat.com> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/mm.h | 2 +- rust/bindings/bindings_helper.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) --- a/include/linux/mm.h~mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise +++ a/include/linux/mm.h @@ -323,7 +323,7 @@ extern unsigned int kobjsize(const void #define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */ #define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */ #define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */ -#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */ +#define VM_MERGEABLE BIT(31) /* KSM may merge identical pages */ #ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS #define VM_HIGH_ARCH_BIT_0 32 /* bit only usable on 64-bit architectures */ --- a/rust/bindings/bindings_helper.h~mm-ksm-fix-flag-dropping-behavior-in-ksm_madvise +++ a/rust/bindings/bindings_helper.h @@ -108,6 +108,7 @@ const xa_mark_t RUST_CONST_HELPER_XA_PRE const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC = XA_FLAGS_ALLOC; const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC1 = XA_FLAGS_ALLOC1; +const vm_flags_t RUST_CONST_HELPER_VM_MERGEABLE = VM_MERGEABLE; #if IS_ENABLED(CONFIG_ANDROID_BINDER_IPC_RUST) #include "../../drivers/android/binder/rust_binder.h" _ Patches currently in -mm which might be from acsjakub(a)amazon.de are mm-redefine-vm_-flag-constants-with-bit.patch

4 days, 18 hours

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[merged mm-hotfixes-stable] mm-damon-vaddr-do-not-repeat-pte_offset_map_lock-until-success.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/damon/vaddr: do not repeat pte_offset_map_lock() until success has been removed from the -mm tree. Its filename was mm-damon-vaddr-do-not-repeat-pte_offset_map_lock-until-success.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: SeongJae Park <sj(a)kernel.org> Subject: mm/damon/vaddr: do not repeat pte_offset_map_lock() until success Date: Mon, 29 Sep 2025 17:44:09 -0700 DAMON's virtual address space operation set implementation (vaddr) calls pte_offset_map_lock() inside the page table walk callback function. This is for reading and writing page table accessed bits. If pte_offset_map_lock() fails, it retries by returning the page table walk callback function with ACTION_AGAIN. pte_offset_map_lock() can continuously fail if the target is a pmd migration entry, though. Hence it could cause an infinite page table walk if the migration cannot be done until the page table walk is finished. This indeed caused a soft lockup when CPU hotplugging and DAMON were running in parallel. Avoid the infinite loop by simply not retrying the page table walk. DAMON is promising only a best-effort accuracy, so missing access to such pages is no problem. Link: https://lkml.kernel.org/r/20250930004410.55228-1-sj@kernel.org Fixes: 7780d04046a2 ("mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails") Signed-off-by: SeongJae Park <sj(a)kernel.org> Reported-by: Xinyu Zheng <zhengxinyu6(a)huawei.com> Closes: https://lore.kernel.org/20250918030029.2652607-1-zhengxinyu6@huawei.com Acked-by: Hugh Dickins <hughd(a)google.com> Cc: <stable(a)vger.kernel.org> [6.5+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/damon/vaddr.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/mm/damon/vaddr.c~mm-damon-vaddr-do-not-repeat-pte_offset_map_lock-until-success +++ a/mm/damon/vaddr.c @@ -328,10 +328,8 @@ static int damon_mkold_pmd_entry(pmd_t * } pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); - if (!pte) { - walk->action = ACTION_AGAIN; + if (!pte) return 0; - } if (!pte_present(ptep_get(pte))) goto out; damon_ptep_mkold(pte, walk->vma, addr); @@ -481,10 +479,8 @@ regular_page: #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); - if (!pte) { - walk->action = ACTION_AGAIN; + if (!pte) return 0; - } ptent = ptep_get(pte); if (!pte_present(ptent)) goto out; _ Patches currently in -mm which might be from sj(a)kernel.org are

4 days, 18 hours

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[merged mm-hotfixes-stable] mm-rmap-fix-soft-dirty-and-uffd-wp-bit-loss-when-remapping-zero-filled-mthp-subpage-to-shared-zeropage.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/rmap: fix soft-dirty and uffd-wp bit loss when remapping zero-filled mTHP subpage to shared zeropage has been removed from the -mm tree. Its filename was mm-rmap-fix-soft-dirty-and-uffd-wp-bit-loss-when-remapping-zero-filled-mthp-subpage-to-shared-zeropage.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Lance Yang <lance.yang(a)linux.dev> Subject: mm/rmap: fix soft-dirty and uffd-wp bit loss when remapping zero-filled mTHP subpage to shared zeropage Date: Tue, 30 Sep 2025 16:10:40 +0800 When splitting an mTHP and replacing a zero-filled subpage with the shared zeropage, try_to_map_unused_to_zeropage() currently drops several important PTE bits. For userspace tools like CRIU, which rely on the soft-dirty mechanism for incremental snapshots, losing the soft-dirty bit means modified pages are missed, leading to inconsistent memory state after restore. As pointed out by David, the more critical uffd-wp bit is also dropped. This breaks the userfaultfd write-protection mechanism, causing writes to be silently missed by monitoring applications, which can lead to data corruption. Preserve both the soft-dirty and uffd-wp bits from the old PTE when creating the new zeropage mapping to ensure they are correctly tracked. Link: https://lkml.kernel.org/r/20250930081040.80926-1-lance.yang@linux.dev Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") Signed-off-by: Lance Yang <lance.yang(a)linux.dev> Suggested-by: David Hildenbrand <david(a)redhat.com> Suggested-by: Dev Jain <dev.jain(a)arm.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Dev Jain <dev.jain(a)arm.com> Acked-by: Zi Yan <ziy(a)nvidia.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Harry Yoo <harry.yoo(a)oracle.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Barry Song <baohua(a)kernel.org> Cc: Byungchul Park <byungchul(a)sk.com> Cc: Gregory Price <gourry(a)gourry.net> Cc: "Huang, Ying" <ying.huang(a)linux.alibaba.com> Cc: Jann Horn <jannh(a)google.com> Cc: Joshua Hahn <joshua.hahnjy(a)gmail.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Mariano Pache <npache(a)redhat.com> Cc: Mathew Brost <matthew.brost(a)intel.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: Rakie Kim <rakie.kim(a)sk.com> Cc: Rik van Riel <riel(a)surriel.com> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Usama Arif <usamaarif642(a)gmail.com> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Yu Zhao <yuzhao(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/migrate.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/mm/migrate.c~mm-rmap-fix-soft-dirty-and-uffd-wp-bit-loss-when-remapping-zero-filled-mthp-subpage-to-shared-zeropage +++ a/mm/migrate.c @@ -296,8 +296,7 @@ bool isolate_folio_to_list(struct folio } static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, - struct folio *folio, - unsigned long idx) + struct folio *folio, pte_t old_pte, unsigned long idx) { struct page *page = folio_page(folio, idx); pte_t newpte; @@ -306,7 +305,7 @@ static bool try_to_map_unused_to_zeropag return false; VM_BUG_ON_PAGE(!PageAnon(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(pte_present(ptep_get(pvmw->pte)), page); + VM_BUG_ON_PAGE(pte_present(old_pte), page); if (folio_test_mlocked(folio) || (pvmw->vma->vm_flags & VM_LOCKED) || mm_forbids_zeropage(pvmw->vma->vm_mm)) @@ -322,6 +321,12 @@ static bool try_to_map_unused_to_zeropag newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address), pvmw->vma->vm_page_prot)); + + if (pte_swp_soft_dirty(old_pte)) + newpte = pte_mksoft_dirty(newpte); + if (pte_swp_uffd_wp(old_pte)) + newpte = pte_mkuffd_wp(newpte); + set_pte_at(pvmw->vma->vm_mm, pvmw->address, pvmw->pte, newpte); dec_mm_counter(pvmw->vma->vm_mm, mm_counter(folio)); @@ -364,13 +369,13 @@ static bool remove_migration_pte(struct continue; } #endif + old_pte = ptep_get(pvmw.pte); if (rmap_walk_arg->map_unused_to_zeropage && - try_to_map_unused_to_zeropage(&pvmw, folio, idx)) + try_to_map_unused_to_zeropage(&pvmw, folio, old_pte, idx)) continue; folio_get(folio); pte = mk_pte(new, READ_ONCE(vma->vm_page_prot)); - old_pte = ptep_get(pvmw.pte); entry = pte_to_swp_entry(old_pte); if (!is_migration_entry_young(entry)) _ Patches currently in -mm which might be from lance.yang(a)linux.dev are hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch mm-khugepaged-abort-collapse-scan-on-non-swap-entries.patch

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[merged mm-hotfixes-stable] mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/thp: fix MTE tag mismatch when replacing zero-filled subpages has been removed from the -mm tree. Its filename was mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Lance Yang <lance.yang(a)linux.dev> Subject: mm/thp: fix MTE tag mismatch when replacing zero-filled subpages Date: Mon, 22 Sep 2025 10:14:58 +0800 From: Lance Yang <lance.yang(a)linux.dev> When both THP and MTE are enabled, splitting a THP and replacing its zero-filled subpages with the shared zeropage can cause MTE tag mismatch faults in userspace. Remapping zero-filled subpages to the shared zeropage is unsafe, as the zeropage has a fixed tag of zero, which may not match the tag expected by the userspace pointer. KSM already avoids this problem by using memcmp_pages(), which on arm64 intentionally reports MTE-tagged pages as non-identical to prevent unsafe merging. As suggested by David[1], this patch adopts the same pattern, replacing the memchr_inv() byte-level check with a call to pages_identical(). This leverages existing architecture-specific logic to determine if a page is truly identical to the shared zeropage. Having both the THP shrinker and KSM rely on pages_identical() makes the design more future-proof, IMO. Instead of handling quirks in generic code, we just let the architecture decide what makes two pages identical. [1] https://lore.kernel.org/all/ca2106a3-4bb2-4457-81af-301fd99fbef4@redhat.com Link: https://lkml.kernel.org/r/20250922021458.68123-1-lance.yang@linux.dev Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") Signed-off-by: Lance Yang <lance.yang(a)linux.dev> Reported-by: Qun-wei Lin <Qun-wei.Lin(a)mediatek.com> Closes: https://lore.kernel.org/all/a7944523fcc3634607691c35311a5d59d1a3f8d4.camel@… Suggested-by: David Hildenbrand <david(a)redhat.com> Acked-by: Zi Yan <ziy(a)nvidia.com> Acked-by: David Hildenbrand <david(a)redhat.com> Acked-by: Usama Arif <usamaarif642(a)gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com> Reviewed-by: Wei Yang <richard.weiyang(a)gmail.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: andrew.yang <andrew.yang(a)mediatek.com> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Barry Song <baohua(a)kernel.org> Cc: Byungchul Park <byungchul(a)sk.com> Cc: Charlie Jenkins <charlie(a)rivosinc.com> Cc: Chinwen Chang <chinwen.chang(a)mediatek.com> Cc: Dev Jain <dev.jain(a)arm.com> Cc: Domenico Cerasuolo <cerasuolodomenico(a)gmail.com> Cc: Gregory Price <gourry(a)gourry.net> Cc: "Huang, Ying" <ying.huang(a)linux.alibaba.com> Cc: Hugh Dickins <hughd(a)google.com> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Joshua Hahn <joshua.hahnjy(a)gmail.com> Cc: Kairui Song <ryncsn(a)gmail.com> Cc: Kalesh Singh <kaleshsingh(a)google.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Mariano Pache <npache(a)redhat.com> Cc: Mathew Brost <matthew.brost(a)intel.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Palmer Dabbelt <palmer(a)rivosinc.com> Cc: Rakie Kim <rakie.kim(a)sk.com> Cc: Rik van Riel <riel(a)surriel.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Samuel Holland <samuel.holland(a)sifive.com> Cc: Shakeel Butt <shakeel.butt(a)linux.dev> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Yu Zhao <yuzhao(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 15 +++------------ mm/migrate.c | 8 +------- 2 files changed, 4 insertions(+), 19 deletions(-) --- a/mm/huge_memory.c~mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages +++ a/mm/huge_memory.c @@ -4104,32 +4104,23 @@ static unsigned long deferred_split_coun static bool thp_underused(struct folio *folio) { int num_zero_pages = 0, num_filled_pages = 0; - void *kaddr; int i; if (khugepaged_max_ptes_none == HPAGE_PMD_NR - 1) return false; for (i = 0; i < folio_nr_pages(folio); i++) { - kaddr = kmap_local_folio(folio, i * PAGE_SIZE); - if (!memchr_inv(kaddr, 0, PAGE_SIZE)) { - num_zero_pages++; - if (num_zero_pages > khugepaged_max_ptes_none) { - kunmap_local(kaddr); + if (pages_identical(folio_page(folio, i), ZERO_PAGE(0))) { + if (++num_zero_pages > khugepaged_max_ptes_none) return true; - } } else { /* * Another path for early exit once the number * of non-zero filled pages exceeds threshold. */ - num_filled_pages++; - if (num_filled_pages >= HPAGE_PMD_NR - khugepaged_max_ptes_none) { - kunmap_local(kaddr); + if (++num_filled_pages >= HPAGE_PMD_NR - khugepaged_max_ptes_none) return false; - } } - kunmap_local(kaddr); } return false; } --- a/mm/migrate.c~mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages +++ a/mm/migrate.c @@ -300,9 +300,7 @@ static bool try_to_map_unused_to_zeropag unsigned long idx) { struct page *page = folio_page(folio, idx); - bool contains_data; pte_t newpte; - void *addr; if (PageCompound(page)) return false; @@ -319,11 +317,7 @@ static bool try_to_map_unused_to_zeropag * this subpage has been non present. If the subpage is only zero-filled * then map it to the shared zeropage. */ - addr = kmap_local_page(page); - contains_data = memchr_inv(addr, 0, PAGE_SIZE); - kunmap_local(addr); - - if (contains_data) + if (!pages_identical(page, ZERO_PAGE(0))) return false; newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address), _ Patches currently in -mm which might be from lance.yang(a)linux.dev are hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch mm-khugepaged-abort-collapse-scan-on-non-swap-entries.patch

4 days, 18 hours

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[merged mm-hotfixes-stable] memcg-skip-cgroup_file_notify-if-spinning-is-not-allowed.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: memcg: skip cgroup_file_notify if spinning is not allowed has been removed from the -mm tree. Its filename was memcg-skip-cgroup_file_notify-if-spinning-is-not-allowed.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Shakeel Butt <shakeel.butt(a)linux.dev> Subject: memcg: skip cgroup_file_notify if spinning is not allowed Date: Mon, 22 Sep 2025 15:02:03 -0700 Generally memcg charging is allowed from all the contexts including NMI where even spinning on spinlock can cause locking issues. However one call chain was missed during the addition of memcg charging from any context support. That is try_charge_memcg() -> memcg_memory_event() -> cgroup_file_notify(). The possible function call tree under cgroup_file_notify() can acquire many different spin locks in spinning mode. Some of them are cgroup_file_kn_lock, kernfs_notify_lock, pool_workqeue's lock. So, let's just skip cgroup_file_notify() from memcg charging if the context does not allow spinning. Alternative approach was also explored where instead of skipping cgroup_file_notify(), we defer the memcg event processing to irq_work [1]. However it adds complexity and it was decided to keep things simple until we need more memcg events with !allow_spinning requirement. Link: https://lore.kernel.org/all/5qi2llyzf7gklncflo6gxoozljbm4h3tpnuv4u4ej4ztysv… [1] Link: https://lkml.kernel.org/r/20250922220203.261714-1-shakeel.butt@linux.dev Fixes: 3ac4638a734a ("memcg: make memcg_rstat_updated nmi safe") Signed-off-by: Shakeel Butt <shakeel.butt(a)linux.dev> Acked-by: Michal Hocko <mhocko(a)suse.com> Closes: https://lore.kernel.org/all/20250905061919.439648-1-yepeilin@google.com/ Cc: Alexei Starovoitov <ast(a)kernel.org> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Kumar Kartikeya Dwivedi <memxor(a)gmail.com> Cc: Muchun Song <muchun.song(a)linux.dev> Cc: Peilin Ye <yepeilin(a)google.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Tejun Heo <tj(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/memcontrol.h | 26 +++++++++++++++++++------- mm/memcontrol.c | 7 ++++--- 2 files changed, 23 insertions(+), 10 deletions(-) --- a/include/linux/memcontrol.h~memcg-skip-cgroup_file_notify-if-spinning-is-not-allowed +++ a/include/linux/memcontrol.h @@ -1001,22 +1001,28 @@ static inline void count_memcg_event_mm( count_memcg_events_mm(mm, idx, 1); } -static inline void memcg_memory_event(struct mem_cgroup *memcg, - enum memcg_memory_event event) +static inline void __memcg_memory_event(struct mem_cgroup *memcg, + enum memcg_memory_event event, + bool allow_spinning) { bool swap_event = event == MEMCG_SWAP_HIGH || event == MEMCG_SWAP_MAX || event == MEMCG_SWAP_FAIL; + /* For now only MEMCG_MAX can happen with !allow_spinning context. */ + VM_WARN_ON_ONCE(!allow_spinning && event != MEMCG_MAX); + atomic_long_inc(&memcg->memory_events_local[event]); - if (!swap_event) + if (!swap_event && allow_spinning) cgroup_file_notify(&memcg->events_local_file); do { atomic_long_inc(&memcg->memory_events[event]); - if (swap_event) - cgroup_file_notify(&memcg->swap_events_file); - else - cgroup_file_notify(&memcg->events_file); + if (allow_spinning) { + if (swap_event) + cgroup_file_notify(&memcg->swap_events_file); + else + cgroup_file_notify(&memcg->events_file); + } if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) break; @@ -1026,6 +1032,12 @@ static inline void memcg_memory_event(st !mem_cgroup_is_root(memcg)); } +static inline void memcg_memory_event(struct mem_cgroup *memcg, + enum memcg_memory_event event) +{ + __memcg_memory_event(memcg, event, true); +} + static inline void memcg_memory_event_mm(struct mm_struct *mm, enum memcg_memory_event event) { --- a/mm/memcontrol.c~memcg-skip-cgroup_file_notify-if-spinning-is-not-allowed +++ a/mm/memcontrol.c @@ -2307,12 +2307,13 @@ static int try_charge_memcg(struct mem_c bool drained = false; bool raised_max_event = false; unsigned long pflags; + bool allow_spinning = gfpflags_allow_spinning(gfp_mask); retry: if (consume_stock(memcg, nr_pages)) return 0; - if (!gfpflags_allow_spinning(gfp_mask)) + if (!allow_spinning) /* Avoid the refill and flush of the older stock */ batch = nr_pages; @@ -2348,7 +2349,7 @@ retry: if (!gfpflags_allow_blocking(gfp_mask)) goto nomem; - memcg_memory_event(mem_over_limit, MEMCG_MAX); + __memcg_memory_event(mem_over_limit, MEMCG_MAX, allow_spinning); raised_max_event = true; psi_memstall_enter(&pflags); @@ -2415,7 +2416,7 @@ force: * a MEMCG_MAX event. */ if (!raised_max_event) - memcg_memory_event(mem_over_limit, MEMCG_MAX); + __memcg_memory_event(mem_over_limit, MEMCG_MAX, allow_spinning); /* * The allocation either can't fail or will lead to more memory _ Patches currently in -mm which might be from shakeel.butt(a)linux.dev are

4 days, 18 hours

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[PATCH v2 00/19 5.15.y] Backport minmax.h updates from v6.17-rc7

by Eliav Farber

This series backports 19 patches to update minmax.h in the 5.15.y branch, aligning it with v6.17-rc7. The ultimate goal is to synchronize all longterm branches so that they include the full set of minmax.h changes (6.12.y and 6.6.y were already backported by me and are now aligned, 6.1.y is in progress). The key motivation is to bring in commit d03eba99f5bf ("minmax: allow min()/max()/clamp() if the arguments have the same signedness"), which is missing in kernel 5.10.y. In mainline, this change enables min()/max()/clamp() to accept mixed argument types, provided both have the same signedness. Without it, backported patches that use these forms may trigger compiler warnings, which escalate to build failures when -Werror is enabled. Changes in v2: - Fix the order of patches 6 - 10 according to order in mainline branch. - Use same style of [ Upstream commit <HASH> ] in all patches. Andy Shevchenko (1): minmax: deduplicate __unconst_integer_typeof() David Laight (8): minmax: fix indentation of __cmp_once() and __clamp_once() minmax.h: add whitespace around operators and after commas minmax.h: update some comments minmax.h: reduce the #define expansion of min(), max() and clamp() minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp() minmax.h: move all the clamp() definitions after the min/max() ones minmax.h: simplify the variants of clamp() minmax.h: remove some #defines that are only expanded once Herve Codina (1): minmax: Introduce {min,max}_array() Linus Torvalds (8): minmax: avoid overly complicated constant expressions in VM code minmax: add a few more MIN_T/MAX_T users minmax: simplify and clarify min_t()/max_t() implementation minmax: make generic MIN() and MAX() macros available everywhere minmax: don't use max() in situations that want a C constant expression minmax: simplify min()/max()/clamp() implementation minmax: improve macro expansion and type checking minmax: fix up min3() and max3() too Matthew Wilcox (Oracle) (1): minmax: add in_range() macro arch/arm/mm/pageattr.c | 6 +- arch/um/drivers/mconsole_user.c | 2 + arch/x86/mm/pgtable.c | 2 +- drivers/edac/sb_edac.c | 4 +- drivers/edac/skx_common.h | 1 - drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 + .../drm/amd/display/modules/hdcp/hdcp_ddc.c | 2 + .../drm/amd/pm/powerplay/hwmgr/ppevvmath.h | 14 +- .../amd/pm/swsmu/smu11/sienna_cichlid_ppt.c | 2 + .../drm/arm/display/include/malidp_utils.h | 2 +- .../display/komeda/komeda_pipeline_state.c | 24 +- drivers/gpu/drm/drm_color_mgmt.c | 2 +- drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 6 - drivers/gpu/drm/radeon/evergreen_cs.c | 2 + drivers/hwmon/adt7475.c | 24 +- drivers/input/touchscreen/cyttsp4_core.c | 2 +- drivers/irqchip/irq-sun6i-r.c | 2 +- drivers/md/dm-integrity.c | 4 +- drivers/media/dvb-frontends/stv0367_priv.h | 3 + .../net/ethernet/chelsio/cxgb3/cxgb3_main.c | 18 +- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +- drivers/net/fjes/fjes_main.c | 4 +- drivers/nfc/pn544/i2c.c | 2 - drivers/platform/x86/sony-laptop.c | 1 - drivers/scsi/isci/init.c | 6 +- .../pci/hive_isp_css_include/math_support.h | 5 - drivers/virt/acrn/ioreq.c | 4 +- fs/btrfs/misc.h | 2 - fs/btrfs/tree-checker.c | 2 +- fs/ext2/balloc.c | 2 - fs/ext4/ext4.h | 2 - fs/ufs/util.h | 6 - include/linux/compiler.h | 9 + include/linux/minmax.h | 264 +++++++++++++----- kernel/trace/preemptirq_delay_test.c | 2 - lib/btree.c | 1 - lib/decompress_unlzma.c | 2 + lib/logic_pio.c | 3 - lib/vsprintf.c | 2 +- lib/zstd/zstd_internal.h | 2 - mm/zsmalloc.c | 1 - net/ipv4/proc.c | 2 +- net/ipv6/proc.c | 2 +- net/netfilter/nf_nat_core.c | 6 +- net/tipc/core.h | 2 +- net/tipc/link.c | 10 +- tools/testing/selftests/vm/mremap_test.c | 2 + 47 files changed, 289 insertions(+), 183 deletions(-) -- 2.47.3

4 days, 18 hours

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[PATCH] phy: exynos5-usbdrd: fix clock prepare imbalance

by André Draszik

Commit f4fb9c4d7f94 ("phy: exynos5-usbdrd: allow DWC3 runtime suspend with UDC bound (E850+)") incorrectly added clk_bulk_disable() as the inverse of clk_bulk_prepare_enable() while it should have of course used clk_bulk_disable_unprepare(). This means incorrect reference counts to the CMU driver remain. Update the code accordingly. Fixes: f4fb9c4d7f94 ("phy: exynos5-usbdrd: allow DWC3 runtime suspend with UDC bound (E850+)") CC: stable(a)vger.kernel.org Signed-off-by: André Draszik <andre.draszik(a)linaro.org> --- drivers/phy/samsung/phy-exynos5-usbdrd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c index a88ba95bdc8f539dd8d908960ee2079905688622..1c8bf80119f11e2cd2f07c829986908c150688ac 100644 --- a/drivers/phy/samsung/phy-exynos5-usbdrd.c +++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c @@ -1823,7 +1823,7 @@ static int exynos5_usbdrd_orien_sw_set(struct typec_switch_dev *sw, phy_drd->orientation = orientation; } - clk_bulk_disable(phy_drd->drv_data->n_clks, phy_drd->clks); + clk_bulk_disable_unprepare(phy_drd->drv_data->n_clks, phy_drd->clks); return 0; } --- base-commit: 3b9b1f8df454caa453c7fb07689064edb2eda90a change-id: 20251006-gs101-usb-phy-clk-imbalance-62eb4e761d55 Best regards, -- André Draszik <andre.draszik(a)linaro.org>

4 days, 18 hours

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[PATCH 6.12.y 6.6.y 6.1.y 5.15.y 5.10.y 5.4.y] ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free

by Jeongjun Park

From: Jeongjun Park <aha310510(a)gmail.com> [ Upstream commit 9f2c0ac1423d5f267e7f1d1940780fc764b0fee3 ] The previous commit 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at removal") patched a UAF issue caused by the error timer. However, because the error timer kill added in this patch occurs after the endpoint delete, a race condition to UAF still occurs, albeit rarely. Additionally, since kill-cleanup for urb is also missing, freed memory can be accessed in interrupt context related to urb, which can cause UAF. Therefore, to prevent this, error timer and urb must be killed before freeing the heap memory. Cc: <stable(a)vger.kernel.org> Reported-by: syzbot+f02665daa2abeef4a947(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f02665daa2abeef4a947 Fixes: 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at removal") Signed-off-by: Jeongjun Park <aha310510(a)gmail.com> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> --- sound/usb/midi.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/sound/usb/midi.c b/sound/usb/midi.c index c3de2b137435..461e183680da 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1522,15 +1522,14 @@ static void snd_usbmidi_free(struct snd_usb_midi *umidi) { int i; + if (!umidi->disconnected) + snd_usbmidi_disconnect(&umidi->list); + for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) { struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i]; - if (ep->out) - snd_usbmidi_out_endpoint_delete(ep->out); - if (ep->in) - snd_usbmidi_in_endpoint_delete(ep->in); + kfree(ep->out); } mutex_destroy(&umidi->mutex); - timer_shutdown_sync(&umidi->error_timer); kfree(umidi); } --

4 days, 21 hours

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[PATCH] perf: Fix dangling cgroup pointer in cpuctx

by Chris J Arges

From: Yeoreum Yun <yeoreum.yun(a)arm.com> [ Upstream commit 3b7a34aebbdf2a4b7295205bf0c654294283ec82 ] Commit a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bug at task exit") moves the event->state update to before list_del_event(). This makes the event->state test in list_del_event() always false; never calling perf_cgroup_event_disable(). As a result, cpuctx->cgrp won't be cleared properly; causing havoc. Cc: stable(a)vger.kernel.org # 6.6.x, 6.12.x Fixes: a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bug at task exit") Signed-off-by: Chris J Arges <carges(a)cloudflare.com> --- kernel/events/core.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 3cc06ffb60c1..6688660845d2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2100,18 +2100,6 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) if (event->group_leader == event) del_event_from_groups(event, ctx); - /* - * If event was in error state, then keep it - * that way, otherwise bogus counts will be - * returned on read(). The only way to get out - * of error state is by explicit re-enabling - * of the event - */ - if (event->state > PERF_EVENT_STATE_OFF) { - perf_cgroup_event_disable(event, ctx); - perf_event_set_state(event, PERF_EVENT_STATE_OFF); - } - ctx->generation++; event->pmu_ctx->nr_events--; } @@ -2456,11 +2444,14 @@ __perf_remove_from_context(struct perf_event *event, */ if (flags & DETACH_EXIT) state = PERF_EVENT_STATE_EXIT; - if (flags & DETACH_DEAD) { - event->pending_disable = 1; + if (flags & DETACH_DEAD) state = PERF_EVENT_STATE_DEAD; - } + event_sched_out(event, ctx); + + if (event->state > PERF_EVENT_STATE_OFF) + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, min(event->state, state)); if (flags & DETACH_GROUP) perf_group_detach(event); -- 2.43.0

4 days, 22 hours

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[PATCH net] xsk: Fix overflow in descriptor validation@@

by Ilia Gavrilov

The desc->len value can be set up to U32_MAX. If umem tx_metadata_len option is also set, then the value of the expression 'desc->len + pool->tx_metadata_len' can overflow and validation of the incorrect descriptor will be successfully passed. This can lead to a subsequent chain of arithmetic overflows in the xsk_build_skb() function and incorrect sk_buff allocation. Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 341ac980eab9 ("xsk: Support tx_metadata_len") Cc: stable(a)vger.kernel.org Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov(a)infotecs.ru> --- net/xdp/xsk_queue.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index f16f390370dc..b206a8839b39 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -144,7 +144,7 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { u64 addr = desc->addr - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; + u64 len = (u64)desc->len + pool->tx_metadata_len; u64 offset = addr & (pool->chunk_size - 1); if (!desc->len) @@ -165,7 +165,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; + u64 len = (u64)desc->len + pool->tx_metadata_len; if (!desc->len) return false; -- 2.39.5

5 days, 1 hour

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[PATCH net v2] xsk: Fix overflow in descriptor validation

by Ilia Gavrilov

The desc->len value can be set up to U32_MAX. If umem tx_metadata_len option is also set, the value of the expression 'desc->len + pool->tx_metadata_len' can overflow and validation of the incorrect descriptor will be successfully passed. This can lead to a subsequent chain of arithmetic overflows in the xsk_build_skb() function and incorrect sk_buff allocation. To reproduce the overflow, this piece of userspace code can be used: struct xdp_umem_reg umem_reg; umem_reg.addr = (__u64)(void *)umem; ... umem_reg.chunk_size = 4096; umem_reg.tx_metadata_len = 16; umem_reg.flags = XDP_UMEM_TX_METADATA_LEN; setsockopt(sfd, SOL_XDP, XDP_UMEM_REG, &umem_reg, sizeof(umem_reg)); ... xsk_ring_prod__reserve(tq, batch_size, &idx); for (i = 0; i < nr_packets; ++i) { struct xdp_desc *tx_desc = xsk_ring_prod__tx_desc(tq, idx + i); tx_desc->addr = packets[i].addr; tx_desc->addr += umem->tx_metadata_len; tx_desc->options = XDP_TX_METADATA; tx_desc->len = UINT32_MAX; } xsk_ring_prod__submit(tq, nr_packets); ... sendto(sfd, NULL, 0, MSG_DONTWAIT, NULL, 0); Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 341ac980eab9 ("xsk: Support tx_metadata_len") Cc: stable(a)vger.kernel.org Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov(a)infotecs.ru> --- v2: Add a repro net/xdp/xsk_queue.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index f16f390370dc..b206a8839b39 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -144,7 +144,7 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { u64 addr = desc->addr - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; + u64 len = (u64)desc->len + pool->tx_metadata_len; u64 offset = addr & (pool->chunk_size - 1); if (!desc->len) @@ -165,7 +165,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; + u64 len = (u64)desc->len + pool->tx_metadata_len; if (!desc->len) return false; -- 2.39.5

5 days, 1 hour

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[PATCH] ext4: free orphan info with kvfree

by Jan Kara

Orphan info is now getting allocated with kvmalloc_array(). Free it with kvfree() instead of kfree() to avoid complaints from mm. Reported-by: Chris Mason <clm(a)meta.com> Fixes: 0a6ce20c1564 ("ext4: verify orphan file size is not too big") CC: stable(a)vger.kernel.org Signed-off-by: Jan Kara <jack(a)suse.cz> --- fs/ext4/orphan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c index 33c3a89396b1..82d5e7501455 100644 --- a/fs/ext4/orphan.c +++ b/fs/ext4/orphan.c @@ -513,7 +513,7 @@ void ext4_release_orphan_info(struct super_block *sb) return; for (i = 0; i < oi->of_blocks; i++) brelse(oi->of_binfo[i].ob_bh); - kfree(oi->of_binfo); + kvfree(oi->of_binfo); } static struct ext4_orphan_block_tail *ext4_orphan_block_tail( @@ -637,7 +637,7 @@ int ext4_init_orphan_info(struct super_block *sb) out_free: for (i--; i >= 0; i--) brelse(oi->of_binfo[i].ob_bh); - kfree(oi->of_binfo); + kvfree(oi->of_binfo); out_put: iput(inode); return ret; -- 2.51.0

5 days, 1 hour

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LR compute WA

by Mario Limonciello (AMD) (kernel.org)

Hi, We have some reports of long compute jobs on APUs hanging the system. This has been root caused and a workaround has been introduced in the mainline kernel. I didn't CC stable on the original W/A because I wanted to make sure we've had enough time to test it didn't have unintended side effects. I feel comfortable with the testing at this point and I think it's worth bringing back to any stable kernels it will apply to 6.12.y and newer. The commit is: 1fb710793ce2619223adffaf981b1ff13cd48f17 Thanks,

5 days, 2 hours

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