July 2025 - Linux-stable-mirror

[PATCH v3 1/1] mm/rmap: fix potential out-of-bounds page table access during batched unmap

by Lance Yang

From: Lance Yang <lance.yang(a)linux.dev> As pointed out by David[1], the batched unmap logic in try_to_unmap_one() may read past the end of a PTE table when a large folio's PTE mappings are not fully contained within a single page table. While this scenario might be rare, an issue triggerable from userspace must be fixed regardless of its likelihood. This patch fixes the out-of-bounds access by refactoring the logic into a new helper, folio_unmap_pte_batch(). The new helper correctly calculates the safe batch size by capping the scan at both the VMA and PMD boundaries. To simplify the code, it also supports partial batching (i.e., any number of pages from 1 up to the calculated safe maximum), as there is no strong reason to special-case for fully mapped folios. [1] https://lore.kernel.org/linux-mm/a694398c-9f03-4737-81b9-7e49c857fcbe@redha… Fixes: 354dffd29575 ("mm: support batched unmap for lazyfree large folios during reclamation") Cc: <stable(a)vger.kernel.org> Acked-by: Barry Song <baohua(a)kernel.org> Suggested-by: David Hildenbrand <david(a)redhat.com> Suggested-by: Barry Song <baohua(a)kernel.org> Signed-off-by: Lance Yang <lance.yang(a)linux.dev> --- v2 -> v3: - Tweak changelog (per Barry and David) - Pick AB from Barry - thanks! - https://lore.kernel.org/linux-mm/20250627062319.84936-1-lance.yang@linux.dev v1 -> v2: - Update subject and changelog (per Barry) - https://lore.kernel.org/linux-mm/20250627025214.30887-1-lance.yang@linux.dev mm/rmap.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index fb63d9256f09..1320b88fab74 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1845,23 +1845,32 @@ void folio_remove_rmap_pud(struct folio *folio, struct page *page, #endif } -/* We support batch unmapping of PTEs for lazyfree large folios */ -static inline bool can_batch_unmap_folio_ptes(unsigned long addr, - struct folio *folio, pte_t *ptep) +static inline unsigned int folio_unmap_pte_batch(struct folio *folio, + struct page_vma_mapped_walk *pvmw, + enum ttu_flags flags, pte_t pte) { const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY; - int max_nr = folio_nr_pages(folio); - pte_t pte = ptep_get(ptep); + unsigned long end_addr, addr = pvmw->address; + struct vm_area_struct *vma = pvmw->vma; + unsigned int max_nr; + + if (flags & TTU_HWPOISON) + return 1; + if (!folio_test_large(folio)) + return 1; + /* We may only batch within a single VMA and a single page table. */ + end_addr = pmd_addr_end(addr, vma->vm_end); + max_nr = (end_addr - addr) >> PAGE_SHIFT; + + /* We only support lazyfree batching for now ... */ if (!folio_test_anon(folio) || folio_test_swapbacked(folio)) - return false; + return 1; if (pte_unused(pte)) - return false; - if (pte_pfn(pte) != folio_pfn(folio)) - return false; + return 1; - return folio_pte_batch(folio, addr, ptep, pte, max_nr, fpb_flags, NULL, - NULL, NULL) == max_nr; + return folio_pte_batch(folio, addr, pvmw->pte, pte, max_nr, fpb_flags, + NULL, NULL, NULL); } /* @@ -2024,9 +2033,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, if (pte_dirty(pteval)) folio_mark_dirty(folio); } else if (likely(pte_present(pteval))) { - if (folio_test_large(folio) && !(flags & TTU_HWPOISON) && - can_batch_unmap_folio_ptes(address, folio, pvmw.pte)) - nr_pages = folio_nr_pages(folio); + nr_pages = folio_unmap_pte_batch(folio, &pvmw, flags, pteval); end_addr = address + nr_pages * PAGE_SIZE; flush_cache_range(vma, address, end_addr); @@ -2206,13 +2213,16 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, hugetlb_remove_rmap(folio); } else { folio_remove_rmap_ptes(folio, subpage, nr_pages, vma); - folio_ref_sub(folio, nr_pages - 1); } if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); - folio_put(folio); - /* We have already batched the entire folio */ - if (nr_pages > 1) + folio_put_refs(folio, nr_pages); + + /* + * If we are sure that we batched the entire folio and cleared + * all PTEs, we can just optimize and stop right here. + */ + if (nr_pages == folio_nr_pages(folio)) goto walk_done; continue; walk_abort: -- 2.49.0

3 months

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Fix forgotten in stable backports?

by Yann Sionneau

Hello Greg, all, I am wondering if by accident this fix would have been forgotten while backporting to stable branches: 2437513a814b3e93bd02879740a8a06e52e2cf7d ? It has been backported in 6.0 and 6.1: * https://lore.kernel.org/all/20221228144352.366979745@linuxfoundation.org/ * https://lore.kernel.org/all/20221228144356.096159479@linuxfoundation.org/ But not in 5.4, 5.10, 5.15 Even though, indeed, the patch would not apply as such, but it seems trivial to adapt. Downstream XCP-ng (Xen based distribution for virtualization solution) is about to package it https://github.com/xcp-ng-rpms/kernel/pull/20/files (that's how I noticed the lack of backport). Or maybe it was intentional? Thanks for your lights :) Regards, PS: please CC me in answer since I'm not subscribed to stable@ mailing list. -- Yann Sionneau Yann Sionneau | Vates XCP-ng Developer XCP-ng & Xen Orchestra - Vates solutions web: https://vates.tech

3 months

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[PATCH v2 1/4] arm64: dts: imx8mp-venice-gw71xx: fix TPM SPI frequency

by Tim Harvey

The IMX8MPDS Table 37 [1] shows that the max SPI master read frequency depends on the pins the interface is muxed behind with ECSPI2 muxed behind ECSPI2 supporting up to 25MHz. Adjust the spi-max-frequency based on these findings. [1] https://www.nxp.com/webapp/Download?colCode=IMX8MPIEC Fixes: 1a8f6ff6a291 ("arm64: dts: imx8mp-venice-gw71xx: add TPM device") Cc: stable(a)vger.kernel.org Signed-off-by: Tim Harvey <tharvey(a)gateworks.com> --- v2: add cc to stable --- arch/arm64/boot/dts/freescale/imx8mp-venice-gw71xx.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/boot/dts/freescale/imx8mp-venice-gw71xx.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-venice-gw71xx.dtsi index 2f740d74707b..4bf818873fe3 100644 --- a/arch/arm64/boot/dts/freescale/imx8mp-venice-gw71xx.dtsi +++ b/arch/arm64/boot/dts/freescale/imx8mp-venice-gw71xx.dtsi @@ -70,7 +70,7 @@ &ecspi2 { tpm@1 { compatible = "atmel,attpm20p", "tcg,tpm_tis-spi"; reg = <0x1>; - spi-max-frequency = <36000000>; + spi-max-frequency = <25000000>; }; }; -- 2.25.1

3 months

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[PATCH v2] sched: Fix preemption string of preempt_dynamic_none

by Thomas Weißschuh

Zero is a valid value for "preempt_dynamic_mode", namely "preempt_dynamic_none". Fix the off-by-one in preempt_model_str(), so that "preempty_dynamic_none" is correctly formatted as PREEMPT(none) instead of PREEMPT(undef). Fixes: 8bdc5daaa01e ("sched: Add a generic function to return the preemption string") Cc: stable(a)vger.kernel.org Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> Tested-by: Shrikanth Hegde <sshegde(a)linux.ibm.com> Reviewed-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> --- Changes in v2: - Pick up Reviewed-by and Tested-by - Rebase on v6.16-rc1 - Link to v1: https://lore.kernel.org/r/20250603-preempt-str-none-v1-1-f0e9916dcf44@linut… --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dce50fa57471dffc4311b9d393ae300a43d38d20..021b0a703d094b3386c5ba50e0e111e3a7c2b3df 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7663,7 +7663,7 @@ const char *preempt_model_str(void) if (IS_ENABLED(CONFIG_PREEMPT_DYNAMIC)) { seq_buf_printf(&s, "(%s)%s", - preempt_dynamic_mode > 0 ? + preempt_dynamic_mode >= 0 ? preempt_modes[preempt_dynamic_mode] : "undef", brace ? "}" : ""); return seq_buf_str(&s); --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20250603-preempt-str-none-d21231cc2238 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

3 months

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GOOD DAY

by Muhammad Sohaib Manzoor

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3 months

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[PATCH stable] ipmi:msghandler: Fix potential memory corruption in ipmi_create_user()

by Brendan Jackman

From: Dan Carpenter <dan.carpenter(a)linaro.org> commit fa332f5dc6fc662ad7d3200048772c96b861cf6b upstream The "intf" list iterator is an invalid pointer if the correct "intf->intf_num" is not found. Calling atomic_dec(&intf->nr_users) on and invalid pointer will lead to memory corruption. We don't really need to call atomic_dec() if we haven't called atomic_add_return() so update the if (intf->in_shutdown) path as well. Fixes: 8e76741c3d8b ("ipmi: Add a limit on the number of users that may use IPMI") Signed-off-by: Dan Carpenter <dan.carpenter(a)linaro.org> Message-ID: <aBjMZ8RYrOt6NOgi(a)stanley.mountain> Signed-off-by: Corey Minyard <corey(a)minyard.net> Signed-off-by: Brendan Jackman <jackmanb(a)google.com> --- I have tested this in 6.12 with Google's platform drivers added to reproduce the bug. The bug causes the panic notifier chain to get corrupted leading to a crash. With the fix this goes away. Applies to 6.6 too but I haven't tested it there. Backport changes: - Dropped change to the `if (intf->in_shutdown)` block since that logic doesn't exist yet. - Modified out_unlock to release the srcu lock instead of the mutex since we don't have the mutex here yet. --- drivers/char/ipmi/ipmi_msghandler.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index e12b531f5c2f338008a42dc2c35b0a62395c9f3c..6a4a8ecd0edd02793eda70f9f9ae578e37da477f 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -1241,7 +1241,7 @@ int ipmi_create_user(unsigned int if_num, } /* Not found, return an error */ rv = -EINVAL; - goto out_kfree; + goto out_unlock; found: if (atomic_add_return(1, &intf->nr_users) > max_users) { @@ -1283,6 +1283,7 @@ int ipmi_create_user(unsigned int if_num, out_kfree: atomic_dec(&intf->nr_users); +out_unlock: srcu_read_unlock(&ipmi_interfaces_srcu, index); vfree(new_user); return rv; --- base-commit: 783cd2c3dca8b6c434e955b84c20c8940588dc68 change-id: 20250630-ipmi-fix-c565f7098afd Best regards, -- Brendan Jackman <jackmanb(a)google.com>

3 months

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[PATCH v2] drm/xe/bmg: fix compressed VRAM handling

by Matthew Auld

There looks to be an issue in our compression handling when the BO pages are very fragmented, where we choose to skip the identity map and instead fall back to emitting the PTEs by hand when migrating memory, such that we can hopefully do more work per blit operation. However in such a case we need to ensure the src PTEs are correctly tagged with a compression enabled PAT index on dgpu xe2+, otherwise the copy will simply treat the src memory as uncompressed, leading to corruption if the memory was compressed by the user. To fix this pass along use_comp_pat into emit_pte() on the src side, to indicate that compression should be considered. v2 (Jonathan): tweak the commit message Fixes: 523f191cc0c7 ("drm/xe/xe_migrate: Handle migration logic for xe2+ dgfx") Signed-off-by: Matthew Auld <matthew.auld(a)intel.com> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray(a)intel.com> Cc: Thomas Hellström <thomas.hellstrom(a)linux.intel.com> Cc: Akshata Jahagirdar <akshata.jahagirdar(a)intel.com> Cc: <stable(a)vger.kernel.org> # v6.12+ Reviewed-by: Jonathan Cavitt <jonathan.cavitt(a)intel.com> --- drivers/gpu/drm/xe/xe_migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c index 0838582537e8..4e2bdf70eb70 100644 --- a/drivers/gpu/drm/xe/xe_migrate.c +++ b/drivers/gpu/drm/xe/xe_migrate.c @@ -863,7 +863,7 @@ struct dma_fence *xe_migrate_copy(struct xe_migrate *m, if (src_is_vram && xe_migrate_allow_identity(src_L0, &src_it)) xe_res_next(&src_it, src_L0); else - emit_pte(m, bb, src_L0_pt, src_is_vram, copy_system_ccs, + emit_pte(m, bb, src_L0_pt, src_is_vram, copy_system_ccs || use_comp_pat, &src_it, src_L0, src); if (dst_is_vram && xe_migrate_allow_identity(src_L0, &dst_it)) -- 2.50.0

3 months

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[PATCH] x86/mm: Disable hugetlb page table sharing on non-PAE 32-bit

by Jann Horn

Only select ARCH_WANT_HUGE_PMD_SHARE if hugetlb page table sharing is actually possible; page table sharing requires at least three levels, because it involves shared references to PMD tables. Having ARCH_WANT_HUGE_PMD_SHARE enabled on non-PAE 32-bit X86 (which has 2-level paging) became particularly problematic after commit 59d9094df3d7 ("mm: hugetlb: independent PMD page table shared count"), since that changes `struct ptdesc` such that the `pt_mm` (for PGDs) and the `pt_share_count` (for PMDs) share the same union storage - and with 2-level paging, PMDs are PGDs. (For comparison, arm64 also gates ARCH_WANT_HUGE_PMD_SHARE on the configuration of page tables such that it is never enabled with 2-level paging.) Reported-by: Vitaly Chikunov <vt(a)altlinux.org> Closes: https://lore.kernel.org/r/srhpjxlqfna67blvma5frmy3aa@altlinux.org Fixes: cfe28c5d63d8 ("x86: mm: Remove x86 version of huge_pmd_share.") Cc: stable(a)vger.kernel.org Signed-off-by: Jann Horn <jannh(a)google.com> --- arch/x86/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 71019b3b54ea..917f523b994b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -147,7 +147,7 @@ config X86 select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANTS_NO_INSTR select ARCH_WANT_GENERAL_HUGETLB - select ARCH_WANT_HUGE_PMD_SHARE + select ARCH_WANT_HUGE_PMD_SHARE if PGTABLE_LEVELS > 2 select ARCH_WANT_LD_ORPHAN_WARN select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 --- base-commit: d0b3b7b22dfa1f4b515fd3a295b3fd958f9e81af change-id: 20250630-x86-2level-hugetlb-b1d8feb255ce -- Jann Horn <jannh(a)google.com>

3 months

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[PATCH] fs: Prevent file descriptor table allocations exceeding INT_MAX

by Sasha Levin

When sysctl_nr_open is set to a very high value (for example, 1073741816 as set by systemd), processes attempting to use file descriptors near the limit can trigger massive memory allocation attempts that exceed INT_MAX, resulting in a WARNING in mm/slub.c: WARNING: CPU: 0 PID: 44 at mm/slub.c:5027 __kvmalloc_node_noprof+0x21a/0x288 This happens because kvmalloc_array() and kvmalloc() check if the requested size exceeds INT_MAX and emit a warning when the allocation is not flagged with __GFP_NOWARN. Specifically, when nr_open is set to 1073741816 (0x3ffffff8) and a process calls dup2(oldfd, 1073741880), the kernel attempts to allocate: - File descriptor array: 1073741880 * 8 bytes = 8,589,935,040 bytes - Multiple bitmaps: ~400MB - Total allocation size: > 8GB (exceeding INT_MAX = 2,147,483,647) Reproducer: 1. Set /proc/sys/fs/nr_open to 1073741816: # echo 1073741816 > /proc/sys/fs/nr_open 2. Run a program that uses a high file descriptor: #include <unistd.h> #include <sys/resource.h> int main() { struct rlimit rlim = {1073741824, 1073741824}; setrlimit(RLIMIT_NOFILE, &rlim); dup2(2, 1073741880); // Triggers the warning return 0; } 3. Observe WARNING in dmesg at mm/slub.c:5027 systemd commit a8b627a introduced automatic bumping of fs.nr_open to the maximum possible value. The rationale was that systems with memory control groups (memcg) no longer need separate file descriptor limits since memory is properly accounted. However, this change overlooked that: 1. The kernel's allocation functions still enforce INT_MAX as a maximum size regardless of memcg accounting 2. Programs and tests that legitimately test file descriptor limits can inadvertently trigger massive allocations 3. The resulting allocations (>8GB) are impractical and will always fail systemd's algorithm starts with INT_MAX and keeps halving the value until the kernel accepts it. On most systems, this results in nr_open being set to 1073741816 (0x3ffffff8), which is just under 1GB of file descriptors. While processes rarely use file descriptors near this limit in normal operation, certain selftests (like tools/testing/selftests/core/unshare_test.c) and programs that test file descriptor limits can trigger this issue. Fix this by adding a check in alloc_fdtable() to ensure the requested allocation size does not exceed INT_MAX. This causes the operation to fail with -EMFILE instead of triggering a kernel warning and avoids the impractical >8GB memory allocation request. Fixes: 9cfe015aa424 ("get rid of NR_OPEN and introduce a sysctl_nr_open") Cc: stable(a)vger.kernel.org Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- fs/file.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/file.c b/fs/file.c index b6db031545e65..6d2275c3be9c6 100644 --- a/fs/file.c +++ b/fs/file.c @@ -197,6 +197,21 @@ static struct fdtable *alloc_fdtable(unsigned int slots_wanted) return ERR_PTR(-EMFILE); } + /* + * Check if the allocation size would exceed INT_MAX. kvmalloc_array() + * and kvmalloc() will warn if the allocation size is greater than + * INT_MAX, as filp_cachep objects are not __GFP_NOWARN. + * + * This can happen when sysctl_nr_open is set to a very high value and + * a process tries to use a file descriptor near that limit. For example, + * if sysctl_nr_open is set to 1073741816 (0x3ffffff8) - which is what + * systemd typically sets it to - then trying to use a file descriptor + * close to that value will require allocating a file descriptor table + * that exceeds 8GB in size. + */ + if (unlikely(nr > INT_MAX / sizeof(struct file *))) + return ERR_PTR(-EMFILE); + fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL_ACCOUNT); if (!fdt) goto out; -- 2.39.5

3 months

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[PATCH 1/1] usb: cdnsp: do not disable slot for disabled slot

by Peter Chen

It doesn't need to do it, and the related command event returns 'Slot Not Enabled Error' status. Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver") cc: stable(a)vger.kernel.org Suggested-by: Hongliang Yang <hongliang.yang(a)cixtech.com> Signed-off-by: Peter Chen <peter.chen(a)cixtech.com> --- drivers/usb/cdns3/cdnsp-ring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c index fd06cb85c4ea..757fdd918286 100644 --- a/drivers/usb/cdns3/cdnsp-ring.c +++ b/drivers/usb/cdns3/cdnsp-ring.c @@ -772,7 +772,9 @@ static int cdnsp_update_port_id(struct cdnsp_device *pdev, u32 port_id) } if (port_id != old_port) { - cdnsp_disable_slot(pdev); + if (pdev->slot_id) + cdnsp_disable_slot(pdev); + pdev->active_port = port; cdnsp_enable_slot(pdev); } -- 2.25.1

3 months

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