July 2025 - Linux-stable-mirror

[PATCH] mm/userfaultfd: fix missing PTE unmap for non-migration entries

by Sasha Levin

When handling non-swap entries in move_pages_pte(), the error handling for entries that are NOT migration entries fails to unmap the page table entries before jumping to the error handling label. This results in a kmap/kunmap imbalance which on CONFIG_HIGHPTE systems triggers a WARNING in kunmap_local_indexed() because the kmap stack is corrupted. Example call trace on ARM32 (CONFIG_HIGHPTE enabled): WARNING: CPU: 1 PID: 633 at mm/highmem.c:622 kunmap_local_indexed+0x178/0x17c Call trace: kunmap_local_indexed from move_pages+0x964/0x19f4 move_pages from userfaultfd_ioctl+0x129c/0x2144 userfaultfd_ioctl from sys_ioctl+0x558/0xd24 The issue was introduced with the UFFDIO_MOVE feature but became more frequent with the addition of guard pages (commit 7c53dfbdb024 ("mm: add PTE_MARKER_GUARD PTE marker")) which made the non-migration entry code path more commonly executed during userfaultfd operations. Fix this by ensuring PTEs are properly unmapped in all non-swap entry paths before jumping to the error handling label, not just for migration entries. Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Cc: stable(a)vger.kernel.org Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- mm/userfaultfd.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 8253978ee0fb1..7c298e9cbc18f 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1384,14 +1384,15 @@ static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, entry = pte_to_swp_entry(orig_src_pte); if (non_swap_entry(entry)) { + pte_unmap(src_pte); + pte_unmap(dst_pte); + src_pte = dst_pte = NULL; if (is_migration_entry(entry)) { - pte_unmap(src_pte); - pte_unmap(dst_pte); - src_pte = dst_pte = NULL; migration_entry_wait(mm, src_pmd, src_addr); err = -EAGAIN; - } else + } else { err = -EFAULT; + } goto out; } -- 2.39.5

4 months, 2 weeks

5
22
0 0

[PATCH 5.15.y] KVM: arm64: sys_regs: disable -Wuninitialized-const-pointer warning

by Justin Stitt

A new warning in Clang 22 [1] complains that @clidr passed to get_clidr_el1() is an uninitialized const pointer. get_clidr_el1() doesn't really care since it casts away the const-ness anyways -- it is a false positive. | ../arch/arm64/kvm/sys_regs.c:2838:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] | 2838 | get_clidr_el1(NULL, &clidr); /* Ugly... */ | | ^~~~~ Disable this warning for sys_regs.o with an iron fist as it doesn't make sense to waste maintainer's time or potentially break builds by backporting large changelists from 6.2+. This patch isn't needed for anything past 6.1 as this code section was reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache configuration"). Cc: stable(a)vger.kernel.org Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d44… [1] Signed-off-by: Justin Stitt <justinstitt(a)google.com> --- I'm sending a similar patch for 6.1. --- arch/arm64/kvm/Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 989bb5dad2c8..109cca425d3e 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -25,3 +25,6 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \ vgic/vgic-its.o vgic/vgic-debug.o kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o + +# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer) --- base-commit: 8bb7eca972ad531c9b149c0a51ab43a417385813 change-id: 20250728-b4-stable-disable-uninit-ptr-warn-5-15-c0c9db3df206 Best regards, -- Justin Stitt <justinstitt(a)google.com>

4 months, 2 weeks

3
2
0 0

[PATCH 6.1.y] KVM: arm64: sys_regs: disable -Wuninitialized-const-pointer warning

by Justin Stitt

A new warning in Clang 22 [1] complains that @clidr passed to get_clidr_el1() is an uninitialized const pointer. get_clidr_el1() doesn't really care since it casts away the const-ness anyways -- it is a false positive. | ../arch/arm64/kvm/sys_regs.c:2978:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] | 2978 | get_clidr_el1(NULL, &clidr); /* Ugly... */ | | ^~~~~ Disable this warning for sys_regs.o with an iron fist as it doesn't make sense to waste maintainer's time or potentially break builds by backporting large changelists from 6.2+. This patch isn't needed for anything past 6.1 as this code section was reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache configuration"). Cc: stable(a)vger.kernel.org Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d44… [1] Signed-off-by: Justin Stitt <justinstitt(a)google.com> --- I've sent a similar patch for 5.15. --- arch/arm64/kvm/Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 5e33c2d4645a..5fdb5331bfad 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -24,6 +24,9 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o +# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer) + always-y := hyp_constants.h hyp-constants.s define rule_gen_hyp_constants --- base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476 change-id: 20250728-stable-disable-unit-ptr-warn-281fee82539c Best regards, -- Justin Stitt <justinstitt(a)google.com>

4 months, 2 weeks

3
2
0 0

[PATCH 5.10.y 0/4] Backport series: "permit write-sealed memfd read-only shared mappings"

by Isaac J. Manjarres

Hello, Until kernel version 6.7, a write-sealed memfd could not be mapped as shared and read-only. This was clearly a bug, and was not inline with the description of F_SEAL_WRITE in the man page for fcntl()[1]. Lorenzo's series [2] fixed that issue and was merged in kernel version 6.7, but was not backported to older kernels. So, this issue is still present on kernels 5.4, 5.10, 5.15, 6.1, and 6.6. This series consists of backports of two of Lorenzo's series [2] and [3]. Note: for [2], I dropped the last patch in that series, since it wouldn't make sense to apply it due to [4] being part of this tree. In lieu of that, I backported [3] to ultimately allow write-sealed memfds to be mapped as read-only. [1] https://man7.org/linux/man-pages/man2/fcntl.2.html [2] https://lore.kernel.org/all/913628168ce6cce77df7d13a63970bae06a526e0.169711… [3] https://lkml.kernel.org/r/99fc35d2c62bd2e05571cf60d9f8b843c56069e0.17328047… [4] https://lore.kernel.org/all/6e0becb36d2f5472053ac5d544c0edfe9b899e25.173022… Lorenzo Stoakes (4): mm: drop the assumption that VM_SHARED always implies writable mm: update memfd seal write check to include F_SEAL_WRITE mm: reinstate ability to map write-sealed memfd mappings read-only selftests/memfd: add test for mapping write-sealed memfd read-only fs/hugetlbfs/inode.c | 2 +- include/linux/fs.h | 4 +- include/linux/memfd.h | 14 ++++ include/linux/mm.h | 80 +++++++++++++++------- kernel/fork.c | 2 +- mm/filemap.c | 2 +- mm/madvise.c | 2 +- mm/memfd.c | 2 +- mm/mmap.c | 10 ++- mm/shmem.c | 2 +- tools/testing/selftests/memfd/memfd_test.c | 43 ++++++++++++ 11 files changed, 129 insertions(+), 34 deletions(-) -- 2.50.1.552.g942d659e1b-goog

4 months, 2 weeks

5
16
0 0

[PATCH v2 1/1] userfaultfd: fix a crash when UFFDIO_MOVE handles a THP hole

by Suren Baghdasaryan

When UFFDIO_MOVE is used with UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES and it encounters a non-present THP, it fails to properly recognize an unmapped hole and tries to access a non-existent folio, resulting in a crash. Add a check to skip non-present THPs. Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") Reported-by: syzbot+b446dbe27035ef6bd6c2(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68794b5c.a70a0220.693ce.0050.GAE@google.com/ Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Cc: stable(a)vger.kernel.org --- Changes since v1 [1] - Fixed step size calculation, per Lokesh Gidra - Added missing check for UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES, per Lokesh Gidra [1] https://lore.kernel.org/all/20250730170733.3829267-1-surenb@google.com/ mm/userfaultfd.c | 45 +++++++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 16 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index cbed91b09640..b5af31c22731 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1818,28 +1818,41 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start, ptl = pmd_trans_huge_lock(src_pmd, src_vma); if (ptl) { - /* Check if we can move the pmd without splitting it. */ - if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) || - !pmd_none(dst_pmdval)) { - struct folio *folio = pmd_folio(*src_pmd); + if (pmd_present(*src_pmd) || is_pmd_migration_entry(*src_pmd)) { + /* Check if we can move the pmd without splitting it. */ + if (move_splits_huge_pmd(dst_addr, src_addr, src_start + len) || + !pmd_none(dst_pmdval)) { + if (pmd_present(*src_pmd)) { + struct folio *folio = pmd_folio(*src_pmd); + + if (!folio || (!is_huge_zero_folio(folio) && + !PageAnonExclusive(&folio->page))) { + spin_unlock(ptl); + err = -EBUSY; + break; + } + } - if (!folio || (!is_huge_zero_folio(folio) && - !PageAnonExclusive(&folio->page))) { spin_unlock(ptl); - err = -EBUSY; - break; + split_huge_pmd(src_vma, src_pmd, src_addr); + /* The folio will be split by move_pages_pte() */ + continue; } + err = move_pages_huge_pmd(mm, dst_pmd, src_pmd, + dst_pmdval, dst_vma, src_vma, + dst_addr, src_addr); + step_size = HPAGE_PMD_SIZE; + } else { spin_unlock(ptl); - split_huge_pmd(src_vma, src_pmd, src_addr); - /* The folio will be split by move_pages_pte() */ - continue; + if (!(mode & UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES)) { + err = -ENOENT; + break; + } + /* nothing to do to move a hole */ + err = 0; + step_size = min(HPAGE_PMD_SIZE, src_start + len - src_addr); } - - err = move_pages_huge_pmd(mm, dst_pmd, src_pmd, - dst_pmdval, dst_vma, src_vma, - dst_addr, src_addr); - step_size = HPAGE_PMD_SIZE; } else { if (pmd_none(*src_pmd)) { if (!(mode & UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES)) { base-commit: 01da54f10fddf3b01c5a3b80f6b16bbad390c302 -- 2.50.1.552.g942d659e1b-goog

4 months, 2 weeks

4
20
0 0

[PATCH] drm/amdgpu/discovery: fix fw based ip discovery

by Alex Deucher

We only need the fw based discovery table for sysfs. No need to parse it. Additionally parsing some of the board specific tables may result in incorrect data on some boards. just load the binary and don't parse it on those boards. Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4441 Fixes: 80a0e8282933 ("drm/amdgpu/discovery: optionally use fw based ip discovery") Cc: stable(a)vger.kernel.org Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 5 +- drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 72 ++++++++++--------- 2 files changed, 41 insertions(+), 36 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index efe98ffb679a4..b2538cff222ce 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -2570,9 +2570,6 @@ static int amdgpu_device_parse_gpu_info_fw(struct amdgpu_device *adev) adev->firmware.gpu_info_fw = NULL; - if (adev->mman.discovery_bin) - return 0; - switch (adev->asic_type) { default: return 0; @@ -2594,6 +2591,8 @@ static int amdgpu_device_parse_gpu_info_fw(struct amdgpu_device *adev) chip_name = "arcturus"; break; case CHIP_NAVI12: + if (adev->mman.discovery_bin) + return 0; chip_name = "navi12"; break; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c index 81b3443c8d7f4..27bd7659961e8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c @@ -2555,40 +2555,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) switch (adev->asic_type) { case CHIP_VEGA10: - case CHIP_VEGA12: - case CHIP_RAVEN: - case CHIP_VEGA20: - case CHIP_ARCTURUS: - case CHIP_ALDEBARAN: - /* this is not fatal. We have a fallback below - * if the new firmwares are not present. some of - * this will be overridden below to keep things - * consistent with the current behavior. + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. */ - r = amdgpu_discovery_reg_base_init(adev); - if (!r) { - amdgpu_discovery_harvest_ip(adev); - amdgpu_discovery_get_gfx_info(adev); - amdgpu_discovery_get_mall_info(adev); - amdgpu_discovery_get_vcn_info(adev); - } - break; - default: - r = amdgpu_discovery_reg_base_init(adev); - if (r) { - drm_err(&adev->ddev, "discovery failed: %d\n", r); - return r; - } - - amdgpu_discovery_harvest_ip(adev); - amdgpu_discovery_get_gfx_info(adev); - amdgpu_discovery_get_mall_info(adev); - amdgpu_discovery_get_vcn_info(adev); - break; - } - - switch (adev->asic_type) { - case CHIP_VEGA10: + amdgpu_discovery_init(adev); vega10_reg_base_init(adev); adev->sdma.num_instances = 2; adev->gmc.num_umc = 4; @@ -2611,6 +2582,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) adev->ip_versions[DCI_HWIP][0] = IP_VERSION(12, 0, 0); break; case CHIP_VEGA12: + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. + */ + amdgpu_discovery_init(adev); vega10_reg_base_init(adev); adev->sdma.num_instances = 2; adev->gmc.num_umc = 4; @@ -2633,6 +2609,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) adev->ip_versions[DCI_HWIP][0] = IP_VERSION(12, 0, 1); break; case CHIP_RAVEN: + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. + */ + amdgpu_discovery_init(adev); vega10_reg_base_init(adev); adev->sdma.num_instances = 1; adev->vcn.num_vcn_inst = 1; @@ -2674,6 +2655,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) } break; case CHIP_VEGA20: + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. + */ + amdgpu_discovery_init(adev); vega20_reg_base_init(adev); adev->sdma.num_instances = 2; adev->gmc.num_umc = 8; @@ -2697,6 +2683,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) adev->ip_versions[DCI_HWIP][0] = IP_VERSION(12, 1, 0); break; case CHIP_ARCTURUS: + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. + */ + amdgpu_discovery_init(adev); arct_reg_base_init(adev); adev->sdma.num_instances = 8; adev->vcn.num_vcn_inst = 2; @@ -2725,6 +2716,11 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) adev->ip_versions[UVD_HWIP][1] = IP_VERSION(2, 5, 0); break; case CHIP_ALDEBARAN: + /* This is not fatal. We only need the discovery + * binary for sysfs. We don't need it for a + * functional system. + */ + amdgpu_discovery_init(adev); aldebaran_reg_base_init(adev); adev->sdma.num_instances = 5; adev->vcn.num_vcn_inst = 2; @@ -2751,6 +2747,16 @@ int amdgpu_discovery_set_ip_blocks(struct amdgpu_device *adev) adev->ip_versions[XGMI_HWIP][0] = IP_VERSION(6, 1, 0); break; default: + r = amdgpu_discovery_reg_base_init(adev); + if (r) { + drm_err(&adev->ddev, "discovery failed: %d\n", r); + return r; + } + + amdgpu_discovery_harvest_ip(adev); + amdgpu_discovery_get_gfx_info(adev); + amdgpu_discovery_get_mall_info(adev); + amdgpu_discovery_get_vcn_info(adev); break; } -- 2.50.1

4 months, 2 weeks

4
4
0 0

[PATCH 1/3] phy: tegra: xusb: fix device and OF node leak at probe

by Johan Hovold

Make sure to drop the references taken to the PMC OF node and device by of_parse_phandle() and of_find_device_by_node() during probe. Note the holding a reference to the PMC device does not prevent the PMC regmap from going away (e.g. if the PMC driver is unbound) so there is no need to keep the reference. Fixes: 2d1021487273 ("phy: tegra: xusb: Add wake/sleepwalk for Tegra210") Cc: stable(a)vger.kernel.org # 5.14 Cc: JC Kuo <jckuo(a)nvidia.com> Signed-off-by: Johan Hovold <johan(a)kernel.org> --- drivers/phy/tegra/xusb-tegra210.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c index ebc8a7e21a31..3409924498e9 100644 --- a/drivers/phy/tegra/xusb-tegra210.c +++ b/drivers/phy/tegra/xusb-tegra210.c @@ -3164,18 +3164,22 @@ tegra210_xusb_padctl_probe(struct device *dev, } pdev = of_find_device_by_node(np); + of_node_put(np); if (!pdev) { dev_warn(dev, "PMC device is not available\n"); goto out; } - if (!platform_get_drvdata(pdev)) + if (!platform_get_drvdata(pdev)) { + put_device(&pdev->dev); return ERR_PTR(-EPROBE_DEFER); + } padctl->regmap = dev_get_regmap(&pdev->dev, "usb_sleepwalk"); if (!padctl->regmap) dev_info(dev, "failed to find PMC regmap\n"); + put_device(&pdev->dev); out: return &padctl->base; } -- 2.49.1

4 months, 2 weeks

2
1
0 0

[PATCH] blk-wbt: Fix io starvation in wbt_rqw_done()

by Julian Sun

Recently, we encountered the following hungtask: INFO: task kworker/11:2:2981147 blocked for more than 6266 seconds "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/11:2 D 0 2981147 2 0x80004000 Workqueue: cgroup_destroy css_free_rwork_fn Call Trace: __schedule+0x934/0xe10 schedule+0x40/0xb0 wb_wait_for_completion+0x52/0x80 ? finish_wait+0x80/0x80 mem_cgroup_css_free+0x3a/0x1b0 css_free_rwork_fn+0x42/0x380 process_one_work+0x1a2/0x360 worker_thread+0x30/0x390 ? create_worker+0x1a0/0x1a0 kthread+0x110/0x130 ? __kthread_cancel_work+0x40/0x40 ret_from_fork+0x1f/0x30 This is because the writeback thread has been continuously and repeatedly throttled by wbt, but at the same time, the writes of another thread proceed quite smoothly. After debugging, I believe it is caused by the following reasons. When thread A is blocked by wbt, the I/O issued by thread B will use a deeper queue depth(rwb->rq_depth.max_depth) because it meets the conditions of wb_recent_wait(), thus allowing thread B's I/O to be issued smoothly and resulting in the inflight I/O of wbt remaining relatively high. However, when I/O completes, due to the high inflight I/O of wbt, the condition "limit - inflight >= rwb->wb_background / 2" in wbt_rqw_done() cannot be satisfied, causing thread A's I/O to remain unable to be woken up. Some on-site information: >>> rwb.rq_depth.max_depth (unsigned int)48 >>> rqw.inflight.counter.value_() 44 >>> rqw.inflight.counter.value_() 35 >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep (unsigned long)3 >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep (unsigned long)2 >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep (unsigned long)20 >>> prog['jiffies'] - rwb.rqos.q.backing_dev_info.last_bdp_sleep (unsigned long)12 cat wb_normal 24 cat wb_background 12 To fix this issue, we can use max_depth in wbt_rqw_done(), so that the handling of wb_recent_wait by wbt_rqw_done() and get_limit() will also be consistent, which is more reasonable. Signed-off-by: Julian Sun <sunjunchao(a)bytedance.com> Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism") --- block/blk-wbt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index a50d4cd55f41..d6a2782d442f 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -210,6 +210,8 @@ static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw, else if (blk_queue_write_cache(rwb->rqos.disk->queue) && !wb_recent_wait(rwb)) limit = 0; + else if (wb_recent_wait(rwb)) + limit = rwb->rq_depth.max_depth; else limit = rwb->wb_normal; -- 2.20.1

4 months, 3 weeks

4
4
0 0

[PATCH] drm/mediatek: Fix device/node reference count leaks in mtk_drm_get_all_drm_priv

by Ma Ke

Using device_find_child() and of_find_device_by_node() to locate devices could cause an imbalance in the device's reference count. device_find_child() and of_find_device_by_node() both call get_device() to increment the reference count of the found device before returning the pointer. In mtk_drm_get_all_drm_priv(), these references are never released through put_device(), resulting in permanent reference count increments. Additionally, the for_each_child_of_node() iterator fails to release node references in all code paths. This leaks device node references when loop termination occurs before reaching MAX_CRTC. These reference count leaks may prevent device/node resources from being properly released during driver unbind operations. As comment of device_find_child() says, 'NOTE: you will need to drop the reference with put_device() after use'. Found by code review. Cc: stable(a)vger.kernel.org Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support") Signed-off-by: Ma Ke <make24(a)iscas.ac.cn> --- drivers/gpu/drm/mediatek/mtk_drm_drv.c | 27 +++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c index 7c0c12dde488..c78186debd3e 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c @@ -388,19 +388,24 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev) of_id = of_match_node(mtk_drm_of_ids, node); if (!of_id) - continue; + goto next; pdev = of_find_device_by_node(node); if (!pdev) - continue; + goto next; drm_dev = device_find_child(&pdev->dev, NULL, mtk_drm_match); - if (!drm_dev) - continue; + if (!drm_dev) { + put_device(&pdev->dev); + goto next; + } temp_drm_priv = dev_get_drvdata(drm_dev); - if (!temp_drm_priv) - continue; + if (!temp_drm_priv) { + put_device(drm_dev); + put_device(&pdev->dev); + goto next; + } if (temp_drm_priv->data->main_len) all_drm_priv[CRTC_MAIN] = temp_drm_priv; @@ -412,10 +417,14 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev) if (temp_drm_priv->mtk_drm_bound) cnt++; - if (cnt == MAX_CRTC) { - of_node_put(node); + put_device(drm_dev); + put_device(&pdev->dev); + +next: + of_node_put(node); + + if (cnt == MAX_CRTC) break; - } } if (drm_priv->data->mmsys_dev_num == cnt) { -- 2.25.1

4 months, 3 weeks

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[PATCH v1 0/6] Backport "x86: fix off-by-one in access_ok()" to 6.6.y

by Jimmy Tran

This patch series backports a critical security fix, identified as CVE-2020-12965 ("Transient Execution of Non-Canonical Accesses"), to the 6.6.y stable kernel tree. commit 573f45a9f9a47fed4c7957609689b772121b33d7 upstream. David Laight (1): x86: fix off-by-one in access_ok() Linus Torvalds (5): vfs: dcache: move hashlen_hash() from callers into d_hash() runtime constants: add default dummy infrastructure runtime constants: add x86 architecture support arm64: add 'runtime constant' support x86: fix user address masking non-canonical speculation issue arch/arm64/include/asm/runtime-const.h | 92 ++++++++++++++++++++++++++ arch/arm64/kernel/vmlinux.lds.S | 3 + arch/x86/include/asm/runtime-const.h | 61 +++++++++++++++++ arch/x86/include/asm/uaccess_64.h | 45 ++++++++----- arch/x86/kernel/cpu/common.c | 10 +++ arch/x86/kernel/vmlinux.lds.S | 4 ++ arch/x86/lib/getuser.S | 9 ++- fs/dcache.c | 17 +++-- include/asm-generic/Kbuild | 1 + include/asm-generic/runtime-const.h | 15 +++++ include/asm-generic/vmlinux.lds.h | 8 +++ 11 files changed, 243 insertions(+), 22 deletions(-) create mode 100644 arch/arm64/include/asm/runtime-const.h create mode 100644 arch/x86/include/asm/runtime-const.h create mode 100644 include/asm-generic/runtime-const.h -- 2.50.0.727.gbf7dc18ff4-goog

4 months, 3 weeks

4
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Linux-stable-mirror July 2025