- Linux-stable-mirror - lists.linaro.org

[PATCH v3] usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths

by Manish Nagar

This patch addresses a race condition caused by unsynchronized execution of multiple call paths invoking `dwc3_remove_requests()`, leading to premature freeing of USB requests and subsequent crashes. Three distinct execution paths interact with `dwc3_remove_requests()`: Path 1: Triggered via `dwc3_gadget_reset_interrupt()` during USB reset handling. The call stack includes: - `dwc3_ep0_reset_state()` - `dwc3_ep0_stall_and_restart()` - `dwc3_ep0_out_start()` - `dwc3_remove_requests()` - `dwc3_gadget_del_and_unmap_request()` Path 2: Also initiated from `dwc3_gadget_reset_interrupt()`, but through `dwc3_stop_active_transfers()`. The call stack includes: - `dwc3_stop_active_transfers()` - `dwc3_remove_requests()` - `dwc3_gadget_del_and_unmap_request()` Path 3: Occurs independently during `adb root` execution, which triggers USB function unbind and bind operations. The sequence includes: - `gserial_disconnect()` - `usb_ep_disable()` - `dwc3_gadget_ep_disable()` - `dwc3_remove_requests()` with `-ESHUTDOWN` status Path 3 operates asynchronously and lacks synchronization with Paths 1 and 2. When Path 3 completes, it disables endpoints and frees 'out' requests. If Paths 1 or 2 are still processing these requests, accessing freed memory leads to a crash due to use-after-free conditions. To fix this added check for request completion and skip processing if already completed and added the request status for ep0 while queue. Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver") Cc: stable(a)vger.kernel.org Suggested-by: Thinh Nguyen <Thinh.Nguyen(a)synopsys.com> Acked-by: Thinh Nguyen <Thinh.Nguyen(a)synopsys.com> Signed-off-by: Manish Nagar <manish.nagar(a)oss.qualcomm.com> --- Changes in v3: - Add the fixes tag , cc stable and acked-by tag. Changes in v2: - Add a check for request completion, in v1 I am avoiding this by wait for completion for ep0 then process the other eps. Link to v2: Link: https://lore.kernel.org/all/20251119171926.1622603-1-manish.nagar@oss.qualc… Link to v1: Link: https://lore.kernel.org/all/20251028080553.618304-1-manish.nagar@oss.qualco… drivers/usb/dwc3/ep0.c | 1 + drivers/usb/dwc3/gadget.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index b4229aa13f37..e0bad5708664 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -94,6 +94,7 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep, req->request.actual = 0; req->request.status = -EINPROGRESS; req->epnum = dep->number; + req->status = DWC3_REQUEST_STATUS_QUEUED; list_add_tail(&req->list, &dep->pending_list); diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 6f18b4840a25..5e4997f974dd 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -228,6 +228,13 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req, { struct dwc3 *dwc = dep->dwc; + /* + * The request might have been processed and completed while the + * spinlock was released. Skip processing if already completed. + */ + if (req->status == DWC3_REQUEST_STATUS_COMPLETED) + return; + dwc3_gadget_del_and_unmap_request(dep, req, status); req->status = DWC3_REQUEST_STATUS_COMPLETED; -- 2.25.1

1 week, 2 days

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Re: it's Seven again for PCBA One-stop Service

by Seven

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1 week, 3 days

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[PATCH net v5 0/5] net: dsa: microchip: Fix resource releases in error path

by Bastien Curutchet (Schneider Electric)

Hi all, I worked on adding PTP support for the KSZ8463. While doing so, I ran into a few bugs in the resource release process that occur when things go wrong arount IRQ initialization. This small series fixes those bugs. The next series, which will add the PTP support, depend on this one. Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet(a)bootlin.com> --- Changes in v5: - All: Add Cc Tag. - PATCH 3: Use dsa_switch_for_each_user_port_continue_reverse() to only iterate over initialized ports. - PATCH 4: Also clean PTP IRQs on port initialization failures - Link to v4: https://lore.kernel.org/r/20251117-ksz-fix-v4-0-13e1da58a492@bootlin.com Changes in v4: - PATCH 1 & 2: Add Andrew's Reviewed-By. - PATCH 3: Ensure ksz_irq is initialized outside of ksz_irq_free() - Add PATCH 4 - PATCH 5: Fix symetry issues in ksz_ptp_msg_irq_{setup/free}() - Link to v3: https://lore.kernel.org/r/20251114-ksz-fix-v3-0-acbb3b9cc32f@bootlin.com Changes in v3: - PATCH 1 and 3: Fix Fixes tags - PATCH 3: Move the irq_dispose_mapping() behind the check that verifies that the domain is initialized - Link to v2: https://lore.kernel.org/r/20251106-ksz-fix-v2-0-07188f608873@bootlin.com Changes in v2: - Add Fixes tag. - Split PATCH 1 in two patches as it needed two different Fixes tags - Add details in commit logs - Link to v1: https://lore.kernel.org/r/20251031-ksz-fix-v1-0-7e46de999ed1@bootlin.com --- Bastien Curutchet (Schneider Electric) (5): net: dsa: microchip: common: Fix checks on irq_find_mapping() net: dsa: microchip: ptp: Fix checks on irq_find_mapping() net: dsa: microchip: Don't free uninitialized ksz_irq net: dsa: microchip: Free previously initialized ports on init failures net: dsa: microchip: Fix symetry in ksz_ptp_msg_irq_{setup/free}() drivers/net/dsa/microchip/ksz_common.c | 34 +++++++++++++++++----------------- drivers/net/dsa/microchip/ksz_ptp.c | 22 +++++++++------------- 2 files changed, 26 insertions(+), 30 deletions(-) --- base-commit: 09652e543e809c2369dca142fee5d9b05be9bdc7 change-id: 20251031-ksz-fix-db345df7635f Best regards, -- Bastien Curutchet (Schneider Electric) <bastien.curutchet(a)bootlin.com>

1 week, 3 days

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[PATCH] scsi: aic94xx: fix use-after-free in device removal path

by moonafterrain＠outlook.com

From: Junrui Luo <moonafterrain(a)outlook.com> The asd_pci_remove() function fails to synchronize with pending tasklets before freeing the asd_ha structure, leading to a potential use-after-free vulnerability. When a device removal is triggered (via hot-unplug or module unload), race condition can occur. The fix adds tasklet_kill() before freeing the asd_ha structure, ensuring all scheduled tasklets complete before cleanup proceeds. Reported-by: Yuhao Jiang <danisjiang(a)gmail.com> Reported-by: Junrui Luo <moonafterrain(a)outlook.com> Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Cc: stable(a)vger.kernel.org Signed-off-by: Junrui Luo <moonafterrain(a)outlook.com> --- drivers/scsi/aic94xx/aic94xx_init.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/aic94xx/aic94xx_init.c b/drivers/scsi/aic94xx/aic94xx_init.c index adf3d9145606..95f3620059f7 100644 --- a/drivers/scsi/aic94xx/aic94xx_init.c +++ b/drivers/scsi/aic94xx/aic94xx_init.c @@ -882,6 +882,9 @@ static void asd_pci_remove(struct pci_dev *dev) asd_disable_ints(asd_ha); + /* Ensure all scheduled tasklets complete before freeing resources */ + tasklet_kill(&asd_ha->seq.dl_tasklet); + asd_remove_dev_attrs(asd_ha); /* XXX more here as needed */ -- 2.51.1.dirty

1 week, 3 days

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[PATCH net 00/11] mptcp: misc fixes for v6.18-rc7

by Matthieu Baerts (NGI0)

Here are various unrelated fixes: - Patch 1: Fix window space computation for fallback connections which can affect ACK generation. A fix for v5.11. - Patch 2: Avoid unneeded subflow-level drops due to unsynced received window. A fix for v5.11. - Patch 3: Avoid premature close for fallback connections with PREEMPT kernels. A fix for v5.12. - Patch 4: Reset instead of fallback in case of data in the MPTCP out-of-order queue. A fix for v5.7. - Patches 5-7: Avoid also sending "plain" TCP reset when closing with an MP_FASTCLOSE. A fix for v6.1. - Patches 8-9: Longer timeout for background connections in MPTCP Join selftests. An additional fix for recent patches for v5.13/v6.1. - Patches 10-11: Fix typo in a check introduce in a recent refactoring. A fix for v6.15. Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Gang Yan (2): mptcp: fix address removal logic in mptcp_pm_nl_rm_addr selftests: mptcp: add a check for 'add_addr_accepted' Matthieu Baerts (NGI0) (3): selftests: mptcp: join: fastclose: remove flaky marks selftests: mptcp: join: endpoints: longer timeout selftests: mptcp: join: userspace: longer timeout Paolo Abeni (6): mptcp: fix ack generation for fallback msk mptcp: avoid unneeded subflow-level drops mptcp: fix premature close in case of fallback mptcp: do not fallback when OoO is present mptcp: decouple mptcp fastclose from tcp close mptcp: fix duplicate reset on fastclose net/mptcp/options.c | 54 +++++++++++++++++++++- net/mptcp/pm_kernel.c | 2 +- net/mptcp/protocol.c | 59 +++++++++++++++++-------- net/mptcp/protocol.h | 3 +- tools/testing/selftests/net/mptcp/mptcp_join.sh | 27 ++++++----- 5 files changed, 113 insertions(+), 32 deletions(-) --- base-commit: 8e0a754b0836d996802713bbebc87bc1cc17925c change-id: 20251117-net-mptcp-misc-fixes-6-18-rc6-835d94cdc095 Best regards, -- Matthieu Baerts (NGI0) <matttbe(a)kernel.org>

1 week, 3 days

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[PATCH] mm/huge_memory: fix NULL pointer deference when splitting shmem folio in swap cache

by Wei Yang

Commit c010d47f107f ("mm: thp: split huge page to any lower order pages") introduced an early check on the folio's order via mapping->flags before proceeding with the split work. This check introduced a bug: for shmem folios in the swap cache, the mapping pointer can be NULL. Accessing mapping->flags in this state leads directly to a NULL pointer dereference. This commit fixes the issue by moving the check for mapping != NULL before any attempt to access mapping->flags. This fix necessarily changes the return value from -EBUSY to -EINVAL when mapping is NULL. After reviewing current callers, they do not differentiate between these two error codes, making this change safe. Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: <stable(a)vger.kernel.org> --- This patch is based on current mm-new, latest commit: 056b93566a35 mm/vmalloc: warn only once when vmalloc detect invalid gfp flags Backport note: Current code evolved from original commit with following four changes. We should do proper adjustment respectively on backporting. commit c010d47f107f609b9f4d6a103b6dfc53889049e9 Author: Zi Yan <ziy(a)nvidia.com> Date: Mon Feb 26 15:55:33 2024 -0500 mm: thp: split huge page to any lower order pages commit 6a50c9b512f7734bc356f4bd47885a6f7c98491a Author: Ran Xiaokai <ran.xiaokai(a)zte.com.cn> Date: Fri Jun 7 17:40:48 2024 +0800 mm: huge_memory: fix misused mapping_large_folio_support() for anon folios commit 9b2f764933eb5e3ac9ebba26e3341529219c4401 Author: Zi Yan <ziy(a)nvidia.com> Date: Wed Jan 22 11:19:27 2025 -0500 mm/huge_memory: allow split shmem large folio to any lower order commit 58729c04cf1092b87aeef0bf0998c9e2e4771133 Author: Zi Yan <ziy(a)nvidia.com> Date: Fri Mar 7 12:39:57 2025 -0500 mm/huge_memory: add buddy allocator like (non-uniform) folio_split() --- mm/huge_memory.c | 68 +++++++++++++++++++++++++----------------------- 1 file changed, 35 insertions(+), 33 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 7c69572b6c3f..8701c3eef05f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3696,29 +3696,42 @@ bool folio_split_supported(struct folio *folio, unsigned int new_order, "Cannot split to order-1 folio"); if (new_order == 1) return false; - } else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) { - if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && - !mapping_large_folio_support(folio->mapping)) { - /* - * We can always split a folio down to a single page - * (new_order == 0) uniformly. - * - * For any other scenario - * a) uniform split targeting a large folio - * (new_order > 0) - * b) any non-uniform split - * we must confirm that the file system supports large - * folios. - * - * Note that we might still have THPs in such - * mappings, which is created from khugepaged when - * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that - * case, the mapping does not actually support large - * folios properly. - */ - VM_WARN_ONCE(warns, - "Cannot split file folio to non-0 order"); + } else { + const struct address_space *mapping = folio->mapping; + + /* Truncated ? */ + /* + * TODO: add support for large shmem folio in swap cache. + * When shmem is in swap cache, mapping is NULL and + * folio_test_swapcache() is true. + */ + if (!mapping) return false; + + if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) { + if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && + !mapping_large_folio_support(folio->mapping)) { + /* + * We can always split a folio down to a + * single page (new_order == 0) uniformly. + * + * For any other scenario + * a) uniform split targeting a large folio + * (new_order > 0) + * b) any non-uniform split + * we must confirm that the file system + * supports large folios. + * + * Note that we might still have THPs in such + * mappings, which is created from khugepaged + * when CONFIG_READ_ONLY_THP_FOR_FS is + * enabled. But in that case, the mapping does + * not actually support large folios properly. + */ + VM_WARN_ONCE(warns, + "Cannot split file folio to non-0 order"); + return false; + } } } @@ -3965,17 +3978,6 @@ static int __folio_split(struct folio *folio, unsigned int new_order, mapping = folio->mapping; - /* Truncated ? */ - /* - * TODO: add support for large shmem folio in swap cache. - * When shmem is in swap cache, mapping is NULL and - * folio_test_swapcache() is true. - */ - if (!mapping) { - ret = -EBUSY; - goto out; - } - min_order = mapping_min_folio_order(folio->mapping); if (new_order < min_order) { ret = -EINVAL; -- 2.34.1

1 week, 3 days

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+ mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/huge_memory: fix NULL pointer deference when splitting folio has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.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: Wei Yang <richard.weiyang(a)gmail.com> Subject: mm/huge_memory: fix NULL pointer deference when splitting folio Date: Wed, 19 Nov 2025 23:53:02 +0000 Commit c010d47f107f ("mm: thp: split huge page to any lower order pages") introduced an early check on the folio's order via mapping->flags before proceeding with the split work. This check introduced a bug: for shmem folios in the swap cache and truncated folios, the mapping pointer can be NULL. Accessing mapping->flags in this state leads directly to a NULL pointer dereference. This commit fixes the issue by moving the check for mapping != NULL before any attempt to access mapping->flags. Link: https://lkml.kernel.org/r/20251119235302.24773-1-richard.weiyang@gmail.com Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Cc: "David Hildenbrand (Red Hat)" <david(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-fix-null-pointer-deference-when-splitting-folio +++ a/mm/huge_memory.c @@ -3619,6 +3619,16 @@ static int __folio_split(struct folio *f if (folio != page_folio(split_at) || folio != page_folio(lock_at)) return -EINVAL; + /* + * Folios that just got truncated cannot get split. Signal to the + * caller that there was a race. + * + * TODO: this will also currently refuse shmem folios that are in the + * swapcache. + */ + if (!is_anon && !folio->mapping) + return -EBUSY; + if (new_order >= folio_order(folio)) return -EINVAL; @@ -3659,18 +3669,6 @@ static int __folio_split(struct folio *f gfp_t gfp; mapping = folio->mapping; - - /* Truncated ? */ - /* - * TODO: add support for large shmem folio in swap cache. - * When shmem is in swap cache, mapping is NULL and - * folio_test_swapcache() is true. - */ - if (!mapping) { - ret = -EBUSY; - goto out; - } - min_order = mapping_min_folio_order(folio->mapping); if (new_order < min_order) { ret = -EINVAL; _ Patches currently in -mm which might be from richard.weiyang(a)gmail.com are mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.patch mm-huge_memory-add-pmd-folio-to-ds_queue-in-do_huge_zero_wp_pmd.patch mm-khugepaged-unify-pmd-folio-installation-with-map_anon_folio_pmd.patch mm-huge_memory-only-get-folio_order-once-during-__folio_split.patch mm-huge_memory-introduce-enum-split_type-for-clarity.patch mm-huge_memory-merge-uniform_split_supported-and-non_uniform_split_supported.patch mm-khugepaged-remove-redundant-clearing-of-struct-collapse_control.patch mm-khugepaged-continue-to-collapse-on-scan_pmd_none.patch mm-khugepaged-unify-scan_pmd_none-and-scan_pmd_null-into-scan_no_pte_table.patch

1 week, 3 days

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[merged] unshare-fix-nsproxy-leak-on-set_cred_ucounts-error-path.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: unshare: fix nsproxy leak on set_cred_ucounts() error path has been removed from the -mm tree. Its filename was unshare-fix-nsproxy-leak-on-set_cred_ucounts-error-path.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Pavel Tikhomirov <ptikhomirov(a)virtuozzo.com> Subject: unshare: fix nsproxy leak on set_cred_ucounts() error path Date: Tue, 18 Nov 2025 14:45:50 +0800 If unshare_nsproxy_namespaces() successfully creates the new_nsproxy, but then set_cred_ucounts() fails, on its error path there is no cleanup for new_nsproxy, so it is leaked. Let's fix that by freeing new_nsproxy if it's not NULL on this error path. Link: https://lkml.kernel.org/r/20251118064552.936962-1-ptikhomirov@virtuozzo.com Fixes: 905ae01c4ae2 ("Add a reference to ucounts for each cred") Signed-off-by: Pavel Tikhomirov <ptikhomirov(a)virtuozzo.com> Acked-by: Alexey Gladkov <legion(a)kernel.org> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Cc: Ben Segall <bsegall(a)google.com> Cc: Dietmar Eggemann <dietmar.eggemann(a)arm.com> Cc: Eric Biederman <ebiederm(a)xmission.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Juri Lelli <juri.lelli(a)redhat.com> Cc: Kees Cook <kees(a)kernel.org> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Mel Gorman <mgorman <mgorman(a)suse.de> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Valentin Schneider <vschneid(a)redhat.com> Cc: Vincent Guittot <vincent.guittot(a)linaro.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Christian Brauner <brauner(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/fork.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/fork.c~unshare-fix-nsproxy-leak-on-set_cred_ucounts-error-path +++ a/kernel/fork.c @@ -3133,8 +3133,11 @@ int ksys_unshare(unsigned long unshare_f if (new_cred) { err = set_cred_ucounts(new_cred); - if (err) + if (err) { + if (new_nsproxy) + free_nsproxy(new_nsproxy); goto bad_unshare_cleanup_cred; + } } if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { _ Patches currently in -mm which might be from ptikhomirov(a)virtuozzo.com are

1 week, 3 days

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[patch 1/1] unshare: fix nsproxy leak on set_cred_ucounts() error path

by Andrew Morton

From: Pavel Tikhomirov <ptikhomirov(a)virtuozzo.com> Subject: unshare: fix nsproxy leak on set_cred_ucounts() error path Date: Tue, 18 Nov 2025 14:45:50 +0800 If unshare_nsproxy_namespaces() successfully creates the new_nsproxy, but then set_cred_ucounts() fails, on its error path there is no cleanup for new_nsproxy, so it is leaked. Let's fix that by freeing new_nsproxy if it's not NULL on this error path. Link: https://lkml.kernel.org/r/20251118064552.936962-1-ptikhomirov@virtuozzo.com Fixes: 905ae01c4ae2a ("Add a reference to ucounts for each cred") Signed-off-by: Pavel Tikhomirov <ptikhomirov(a)virtuozzo.com> Acked-by: Alexey Gladkov <legion(a)kernel.org> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Cc: Ben Segall <bsegall(a)google.com> Cc: Dietmar Eggemann <dietmar.eggemann(a)arm.com> Cc: Eric Biederman <ebiederm(a)xmission.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Juri Lelli <juri.lelli(a)redhat.com> Cc: Kees Cook <kees(a)kernel.org> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Mel Gorman <mgorman <mgorman(a)suse.de> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Valentin Schneider <vschneid(a)redhat.com> Cc: Vincent Guittot <vincent.guittot(a)linaro.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- kernel/fork.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/fork.c~unshare-fix-nsproxy-leak-on-set_cred_ucounts-error-path +++ a/kernel/fork.c @@ -3133,8 +3133,11 @@ int ksys_unshare(unsigned long unshare_f if (new_cred) { err = set_cred_ucounts(new_cred); - if (err) + if (err) { + if (new_nsproxy) + free_nsproxy(new_nsproxy); goto bad_unshare_cleanup_cred; + } } if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) { _

1 week, 3 days

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[PATCH V1 6.1.y 0/2] Fix bad pmd due to race between change_prot_numa() and THP migration

by Harry Yoo

# TL;DR previous discussion: https://lore.kernel.org/linux-mm/b41ea29e-6b48-4f64-859c-73be095453ae@redha… A "bad pmd" error occurs due to race condition between change_prot_numa() and THP migration. The mainline kernel does not have this bug as commit 670ddd8cdc fixes the race condition. 6.1.y, 5.15.y, 5.10.y, 5.4.y are affected by this bug. Fixing this in -stable kernels is tricky because pte_map_offset_lock() has different semantics in pre-6.5 and post-6.5 kernels. I am trying to backport the same mechanism we have in the mainline kernel. Since the code looks bit different due to different semantics of pte_map_offset_lock(), it'd be best to get this reviewed by MM folks. # Testing I verified that the bug described below is not reproduced anymore (on a downstream kernel) after applying this patch series. It used to trigger in few days of intensive numa balancing testing, but it survived 2 weeks with this applied. # Bug Description It was reported that a bad pmd is seen when automatic NUMA balancing is marking page table entries as prot_numa: [2437548.196018] mm/pgtable-generic.c:50: bad pmd 00000000af22fc02(dffffffe71fbfe02) [2437548.235022] Call Trace: [2437548.238234] <TASK> [2437548.241060] dump_stack_lvl+0x46/0x61 [2437548.245689] panic+0x106/0x2e5 [2437548.249497] pmd_clear_bad+0x3c/0x3c [2437548.253967] change_pmd_range.isra.0+0x34d/0x3a7 [2437548.259537] change_p4d_range+0x156/0x20e [2437548.264392] change_protection_range+0x116/0x1a9 [2437548.269976] change_prot_numa+0x15/0x37 [2437548.274774] task_numa_work+0x1b8/0x302 [2437548.279512] task_work_run+0x62/0x95 [2437548.283882] exit_to_user_mode_loop+0x1a4/0x1a9 [2437548.289277] exit_to_user_mode_prepare+0xf4/0xfc [2437548.294751] ? sysvec_apic_timer_interrupt+0x34/0x81 [2437548.300677] irqentry_exit_to_user_mode+0x5/0x25 [2437548.306153] asm_sysvec_apic_timer_interrupt+0x16/0x1b This is due to a race condition between change_prot_numa() and THP migration because the kernel doesn't check is_swap_pmd() and pmd_trans_huge() atomically: change_prot_numa() THP migration ====================================================================== - change_pmd_range() -> is_swap_pmd() returns false, meaning it's not a PMD migration entry. - do_huge_pmd_numa_page() -> migrate_misplaced_page() sets migration entries for the THP. - change_pmd_range() -> pmd_none_or_clear_bad_unless_trans_huge() -> pmd_none() and pmd_trans_huge() returns false - pmd_none_or_clear_bad_unless_trans_huge() -> pmd_bad() returns true for the migration entry! The upstream commit 670ddd8cdcbd ("mm/mprotect: delete pmd_none_or_clear_bad_unless_trans_huge()") closes this race condition by checking is_swap_pmd() and pmd_trans_huge() atomically. # Backporting note commit a79390f5d6a7 ("mm/mprotect: use long for page accountings and retval") is backported to return an error code (negative value) in change_pte_range(). Unlike the mainline, pte_offset_map_lock() does not check if the pmd entry is a migration entry or a hugepage; acquires PTL unconditionally instead of returning failure. Therefore, it is necessary to keep the !is_swap_pmd() && !pmd_trans_huge() && !pmd_devmap() checks in change_pmd_range() before acquiring the PTL. After acquiring the lock, open-code the semantics of pte_offset_map_lock() in the mainline kernel; change_pte_range() fails if the pmd value has changed. This requires adding pmd_old parameter (pmd_t value that is read before calling the function) to change_pte_range(). Hugh Dickins (1): mm/mprotect: delete pmd_none_or_clear_bad_unless_trans_huge() Peter Xu (1): mm/mprotect: use long for page accountings and retval include/linux/hugetlb.h | 4 +- include/linux/mm.h | 2 +- mm/hugetlb.c | 4 +- mm/mempolicy.c | 2 +- mm/mprotect.c | 125 ++++++++++++++++++---------------------- 5 files changed, 61 insertions(+), 76 deletions(-) -- 2.43.0

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