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[PATCH openEuler-1.0-LTS] mm/rmap: fix missing barrier between anon_vma init and vma->anon_vma publish
by Jinjiang Tu 24 Sep '26

24 Sep '26

mainline inclusion from mainline-v7.3 commit b6ac0b3f6013c168f22cad97e79967accacb08e1 category: bugfix bugzilla: https://gitcode.com/openeuler/kernel/issues/10048 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- On arm64 server, we find that a task trying to grab the anon_vma lock triggers hungtask. INFO: task main:2354726 blocked for more than 120 seconds. Tainted: G E 5.10.0-0021.aarch64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:main state:D stack: 0 pid:2354726 ppid:2350673 flags:0x00000a01 Call trace: __switch_to+0x7c/0xbc __schedule+0x3b4/0x8a0 schedule+0x50/0xe0 rwsem_down_write_slowpath+0x3cc/0x6cc down_write+0x60/0x260 __anon_vma_prepare+0x6c/0x210 do_anonymous_page+0x258/0x660 handle_pte_fault+0x188/0x214 __handle_mm_fault+0x1b0/0x380 handle_mm_fault+0xf4/0x284 do_page_fault+0x19c/0x494 do_translation_fault+0xcc/0xf8 do_mem_abort+0x48/0xac el0_da+0x44/0x80 el0_sync_handler+0x88/0xb4 el0_sync+0x160/0x180 After analyzing the vmcore, we found the anon_vma->root->rwsem.count is -1. There is another anon_vma whose anon_vma->root->rwsem.count is 1, the anon_vma->root->rwsem.owner shows the lock is held, but the stack of the task shows the task doesn't hold the anon_vma lock. After adding more debugging info, we found __anon_vma_prepare() reuses anon_vma and triggers the UAF of anon_vma->root due to missing memory barrier, leading to locking and unlocking two different anon_vma->root, thus leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore. This race requires two adjacent VMAs that are not merged but are anon_vma-compatible (e.g., they differ in VMA_ACCESS_FLAGS that can be changed by mprotect()). Two threads fault on each VMA concurrently, both calling __anon_vma_prepare() with only mmap_lock held for reading. THREAD A THREAD B __anon_vma_prepare __anon_vma_prepare find_mergeable_anon_vma() -> NULL anon_vma = anon_vma_alloc(); anon_vma->root = anon_vma; // the two stores may be reordered vma->anon_vma = anon_vma; // finds A's anon_vma anon_vma = find_mergeable_anon_vma(vma); anon_vma_lock_write(anon_vma); // may still see the old root down_write(&anon_vma->root->rwsem); anon_vma_unlock_write(anon_vma); // see the new root, never unlock old up_write(&anon_vma->root->rwsem); thread A triggers page fault and calls __anon_vma_prepare() to prepare anon_vma for the faulting vma. __anon_vma_prepare() allocates and initializes a new anon_vma, and then publishes it to the vma with a plain store. anon_vma_prepare() only requires the mmap_lock to be held for reading, so two threads can fault on adjacent VMAs at the same time. While thread A publishes a new anon_vma, thread B could find the anon_vma via find_mergeable_anon_vma() and then locks anon_vma->root->rwsem. The store to anon_vma->root in anon_vma_alloc() and the store to vma->anon_vma can be reordered. The anon_vma_lock_write() and spin_lock() only provide acquire semantics, which do not prevent prior stores from being reordered after them. The release semantics of the corresponding spin_unlock() and anon_vma_unlock_write() come too late, the store to vma->anon_vma is already published before they take effect. As a result, thread B can observe the following order: vma->anon_vma = anon_vma; anon_vma->root = anon_vma; The anon_vma slab is SLAB_TYPESAFE_BY_RCU, so a newly allocated anon_vma may reuse memory from a previously freed one. The constructor (anon_vma_ctor) does not reset anon_vma->root, and __put_anon_vma() doesn't clear it either, so the old root value persists until anon_vma_alloc() overwrites it. If that store isn't visible, thread B reads a root that points to the old anon_vma and locks it. As a result, thread B can call anon_vma_lock_write() with the old root, and call anon_vma_unlock_write() with the new root, leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore (its count is dropped from 0 to -1 due to wrong unlock). To fix it, change the plain store `vma->anon_vma = anon_vma` to store release, so that the fields of anon_vma are visible before anon_vma is published to vma->anon_vma. At read side, the load of anon_vma and anon_vma->root have address dependency. According to Documentation/memory-barriers.txt and some investigations, only Alpha needs address-dependency barriers and it has been handled by READ_ONCE() in reusable_anon_vma(). We reproduced this issue in v5.10 with KSM enabled. The kernel doesn't merge commit cf7e7a3503df ("mm: prevent KSM from breaking VMA merging for new VMAs"), so there are many adjacent VMAs that aren't merged but are compatible for anon_vma. Without this fix, our production environment could reproduce this issue about 2-5 times each month. After adding a smp_mb() before anon_vma_lock_write(anon_vma) in __anon_vma_prepare(), which is different to this patch, this issue hasn't been reproduced for one month. Link: https://lore.kernel.org/20260908122924.554373-1-tujinjiang@huawei.com Fixes: 5c341ee1dfc8 ("mm: track the root (oldest) anon_vma") Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Reviewed-by: Lance Yang <lance.yang(a)linux.dev> Reviewed-by: Lorenzo Stoakes (ARM) <ljs(a)kernel.org> Acked-by: David Hildenbrand (Arm) <david(a)kernel.org> Acked-by: Vlastimil Babka (SUSE) <vbabka(a)kernel.org> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Harry Yoo <harry(a)kernel.org> Cc: Hiroyouki Kamezawa <kamezawa.hiroyu(a)jp.fujitsu.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com> Cc: Larry Woodman <lwoodman(a)redhat.com> Cc: Liam R. Howlett <liam(a)infradead.org> Cc: Nanyong Sun <sunnanyong(a)huawei.com> Cc: Rik van Riel <riel(a)surriel.com> Cc: <stable(a)vger.kernel.org> Conflicts: mm/rmap.c mm/mmap.c mm/vma.c [Context conflicts.] Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> --- mm/mmap.c | 7 +++++++ mm/rmap.c | 6 +++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index ad643f9dd3a4..7b1e9c28a4cf 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1235,6 +1235,13 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct * * acceptable for merging, so we can do all of this optimistically. But * we do that READ_ONCE() to make sure that we never re-load the pointer. * + * The READ_ONCE() establishes an address dependency between anon_vma and + * any access to its fields, which pairs with the assignment to + * vma->anon_vma performed with release semantics in __anon_vma_prepare(). + * + * This is especially important as anon_vma's are SLAB_TYPESAFE_BY_RCU so + * accessing an uninitialised anon_vma's fields may result in a UAF. + * * IOW: that the "list_is_singular()" test on the anon_vma_chain only * matters for the 'stable anon_vma' case (ie the thing we want to avoid * is to return an anon_vma that is "complex" due to having gone through diff --git a/mm/rmap.c b/mm/rmap.c index e6724fd0617c..78ca23c32cb9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -199,7 +199,11 @@ int __anon_vma_prepare(struct vm_area_struct *vma) /* page_table_lock to protect against threads */ spin_lock(&mm->page_table_lock); if (likely(!vma->anon_vma)) { - vma->anon_vma = anon_vma; + /* + * Make anon_vma fields visible before anon_vma is published. + * Paired with an address dependency in reusable_anon_vma(). + */ + smp_store_release(&vma->anon_vma, anon_vma); anon_vma_chain_link(vma, avc, anon_vma); anon_vma->num_active_vmas++; allocated = NULL; -- 2.43.0

1 0

[PATCH OLK-6.6] mm/rmap: fix missing barrier between anon_vma init and vma->anon_vma publish
by Jinjiang Tu 24 Sep '26

24 Sep '26

mainline inclusion from mainline-v7.3 commit b6ac0b3f6013c168f22cad97e79967accacb08e1 category: bugfix bugzilla: https://gitcode.com/openeuler/kernel/issues/10048 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- On arm64 server, we find that a task trying to grab the anon_vma lock triggers hungtask. INFO: task main:2354726 blocked for more than 120 seconds. Tainted: G E 5.10.0-0021.aarch64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:main state:D stack: 0 pid:2354726 ppid:2350673 flags:0x00000a01 Call trace: __switch_to+0x7c/0xbc __schedule+0x3b4/0x8a0 schedule+0x50/0xe0 rwsem_down_write_slowpath+0x3cc/0x6cc down_write+0x60/0x260 __anon_vma_prepare+0x6c/0x210 do_anonymous_page+0x258/0x660 handle_pte_fault+0x188/0x214 __handle_mm_fault+0x1b0/0x380 handle_mm_fault+0xf4/0x284 do_page_fault+0x19c/0x494 do_translation_fault+0xcc/0xf8 do_mem_abort+0x48/0xac el0_da+0x44/0x80 el0_sync_handler+0x88/0xb4 el0_sync+0x160/0x180 After analyzing the vmcore, we found the anon_vma->root->rwsem.count is -1. There is another anon_vma whose anon_vma->root->rwsem.count is 1, the anon_vma->root->rwsem.owner shows the lock is held, but the stack of the task shows the task doesn't hold the anon_vma lock. After adding more debugging info, we found __anon_vma_prepare() reuses anon_vma and triggers the UAF of anon_vma->root due to missing memory barrier, leading to locking and unlocking two different anon_vma->root, thus leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore. This race requires two adjacent VMAs that are not merged but are anon_vma-compatible (e.g., they differ in VMA_ACCESS_FLAGS that can be changed by mprotect()). Two threads fault on each VMA concurrently, both calling __anon_vma_prepare() with only mmap_lock held for reading. THREAD A THREAD B __anon_vma_prepare __anon_vma_prepare find_mergeable_anon_vma() -> NULL anon_vma = anon_vma_alloc(); anon_vma->root = anon_vma; // the two stores may be reordered vma->anon_vma = anon_vma; // finds A's anon_vma anon_vma = find_mergeable_anon_vma(vma); anon_vma_lock_write(anon_vma); // may still see the old root down_write(&anon_vma->root->rwsem); anon_vma_unlock_write(anon_vma); // see the new root, never unlock old up_write(&anon_vma->root->rwsem); thread A triggers page fault and calls __anon_vma_prepare() to prepare anon_vma for the faulting vma. __anon_vma_prepare() allocates and initializes a new anon_vma, and then publishes it to the vma with a plain store. anon_vma_prepare() only requires the mmap_lock to be held for reading, so two threads can fault on adjacent VMAs at the same time. While thread A publishes a new anon_vma, thread B could find the anon_vma via find_mergeable_anon_vma() and then locks anon_vma->root->rwsem. The store to anon_vma->root in anon_vma_alloc() and the store to vma->anon_vma can be reordered. The anon_vma_lock_write() and spin_lock() only provide acquire semantics, which do not prevent prior stores from being reordered after them. The release semantics of the corresponding spin_unlock() and anon_vma_unlock_write() come too late, the store to vma->anon_vma is already published before they take effect. As a result, thread B can observe the following order: vma->anon_vma = anon_vma; anon_vma->root = anon_vma; The anon_vma slab is SLAB_TYPESAFE_BY_RCU, so a newly allocated anon_vma may reuse memory from a previously freed one. The constructor (anon_vma_ctor) does not reset anon_vma->root, and __put_anon_vma() doesn't clear it either, so the old root value persists until anon_vma_alloc() overwrites it. If that store isn't visible, thread B reads a root that points to the old anon_vma and locks it. As a result, thread B can call anon_vma_lock_write() with the old root, and call anon_vma_unlock_write() with the new root, leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore (its count is dropped from 0 to -1 due to wrong unlock). To fix it, change the plain store `vma->anon_vma = anon_vma` to store release, so that the fields of anon_vma are visible before anon_vma is published to vma->anon_vma. At read side, the load of anon_vma and anon_vma->root have address dependency. According to Documentation/memory-barriers.txt and some investigations, only Alpha needs address-dependency barriers and it has been handled by READ_ONCE() in reusable_anon_vma(). We reproduced this issue in v5.10 with KSM enabled. The kernel doesn't merge commit cf7e7a3503df ("mm: prevent KSM from breaking VMA merging for new VMAs"), so there are many adjacent VMAs that aren't merged but are compatible for anon_vma. Without this fix, our production environment could reproduce this issue about 2-5 times each month. After adding a smp_mb() before anon_vma_lock_write(anon_vma) in __anon_vma_prepare(), which is different to this patch, this issue hasn't been reproduced for one month. Link: https://lore.kernel.org/20260908122924.554373-1-tujinjiang@huawei.com Fixes: 5c341ee1dfc8 ("mm: track the root (oldest) anon_vma") Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Reviewed-by: Lance Yang <lance.yang(a)linux.dev> Reviewed-by: Lorenzo Stoakes (ARM) <ljs(a)kernel.org> Acked-by: David Hildenbrand (Arm) <david(a)kernel.org> Acked-by: Vlastimil Babka (SUSE) <vbabka(a)kernel.org> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Harry Yoo <harry(a)kernel.org> Cc: Hiroyouki Kamezawa <kamezawa.hiroyu(a)jp.fujitsu.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com> Cc: Larry Woodman <lwoodman(a)redhat.com> Cc: Liam R. Howlett <liam(a)infradead.org> Cc: Nanyong Sun <sunnanyong(a)huawei.com> Cc: Rik van Riel <riel(a)surriel.com> Cc: <stable(a)vger.kernel.org> Conflicts: mm/rmap.c mm/mmap.c mm/vma.c [Context conflicts.] Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> --- mm/mmap.c | 7 +++++++ mm/rmap.c | 6 +++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index 669bc1b74b35..7b0ba4395441 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1170,6 +1170,13 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct * * acceptable for merging, so we can do all of this optimistically. But * we do that READ_ONCE() to make sure that we never re-load the pointer. * + * The READ_ONCE() establishes an address dependency between anon_vma and + * any access to its fields, which pairs with the assignment to + * vma->anon_vma performed with release semantics in __anon_vma_prepare(). + * + * This is especially important as anon_vma's are SLAB_TYPESAFE_BY_RCU so + * accessing an uninitialised anon_vma's fields may result in a UAF. + * * IOW: that the "list_is_singular()" test on the anon_vma_chain only * matters for the 'stable anon_vma' case (ie the thing we want to avoid * is to return an anon_vma that is "complex" due to having gone through diff --git a/mm/rmap.c b/mm/rmap.c index ad0213898dcd..12718f5ed9d2 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -210,7 +210,11 @@ int __anon_vma_prepare(struct vm_area_struct *vma) /* page_table_lock to protect against threads */ spin_lock(&mm->page_table_lock); if (likely(!vma->anon_vma)) { - vma->anon_vma = anon_vma; + /* + * Make anon_vma fields visible before anon_vma is published. + * Paired with an address dependency in reusable_anon_vma(). + */ + smp_store_release(&vma->anon_vma, anon_vma); anon_vma_chain_link(vma, avc, anon_vma); anon_vma->num_active_vmas++; allocated = NULL; -- 2.43.0

1 0

[PATCH OLK-5.10] mm/rmap: fix missing barrier between anon_vma init and vma->anon_vma publish
by Jinjiang Tu 24 Sep '26

24 Sep '26

mainline inclusion from mainline-v7.3 commit b6ac0b3f6013c168f22cad97e79967accacb08e1 category: bugfix bugzilla: https://gitcode.com/openeuler/kernel/issues/10048 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- On arm64 server, we find that a task trying to grab the anon_vma lock triggers hungtask. INFO: task main:2354726 blocked for more than 120 seconds. Tainted: G E 5.10.0-0021.aarch64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:main state:D stack: 0 pid:2354726 ppid:2350673 flags:0x00000a01 Call trace: __switch_to+0x7c/0xbc __schedule+0x3b4/0x8a0 schedule+0x50/0xe0 rwsem_down_write_slowpath+0x3cc/0x6cc down_write+0x60/0x260 __anon_vma_prepare+0x6c/0x210 do_anonymous_page+0x258/0x660 handle_pte_fault+0x188/0x214 __handle_mm_fault+0x1b0/0x380 handle_mm_fault+0xf4/0x284 do_page_fault+0x19c/0x494 do_translation_fault+0xcc/0xf8 do_mem_abort+0x48/0xac el0_da+0x44/0x80 el0_sync_handler+0x88/0xb4 el0_sync+0x160/0x180 After analyzing the vmcore, we found the anon_vma->root->rwsem.count is -1. There is another anon_vma whose anon_vma->root->rwsem.count is 1, the anon_vma->root->rwsem.owner shows the lock is held, but the stack of the task shows the task doesn't hold the anon_vma lock. After adding more debugging info, we found __anon_vma_prepare() reuses anon_vma and triggers the UAF of anon_vma->root due to missing memory barrier, leading to locking and unlocking two different anon_vma->root, thus leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore. This race requires two adjacent VMAs that are not merged but are anon_vma-compatible (e.g., they differ in VMA_ACCESS_FLAGS that can be changed by mprotect()). Two threads fault on each VMA concurrently, both calling __anon_vma_prepare() with only mmap_lock held for reading. THREAD A THREAD B __anon_vma_prepare __anon_vma_prepare find_mergeable_anon_vma() -> NULL anon_vma = anon_vma_alloc(); anon_vma->root = anon_vma; // the two stores may be reordered vma->anon_vma = anon_vma; // finds A's anon_vma anon_vma = find_mergeable_anon_vma(vma); anon_vma_lock_write(anon_vma); // may still see the old root down_write(&anon_vma->root->rwsem); anon_vma_unlock_write(anon_vma); // see the new root, never unlock old up_write(&anon_vma->root->rwsem); thread A triggers page fault and calls __anon_vma_prepare() to prepare anon_vma for the faulting vma. __anon_vma_prepare() allocates and initializes a new anon_vma, and then publishes it to the vma with a plain store. anon_vma_prepare() only requires the mmap_lock to be held for reading, so two threads can fault on adjacent VMAs at the same time. While thread A publishes a new anon_vma, thread B could find the anon_vma via find_mergeable_anon_vma() and then locks anon_vma->root->rwsem. The store to anon_vma->root in anon_vma_alloc() and the store to vma->anon_vma can be reordered. The anon_vma_lock_write() and spin_lock() only provide acquire semantics, which do not prevent prior stores from being reordered after them. The release semantics of the corresponding spin_unlock() and anon_vma_unlock_write() come too late, the store to vma->anon_vma is already published before they take effect. As a result, thread B can observe the following order: vma->anon_vma = anon_vma; anon_vma->root = anon_vma; The anon_vma slab is SLAB_TYPESAFE_BY_RCU, so a newly allocated anon_vma may reuse memory from a previously freed one. The constructor (anon_vma_ctor) does not reset anon_vma->root, and __put_anon_vma() doesn't clear it either, so the old root value persists until anon_vma_alloc() overwrites it. If that store isn't visible, thread B reads a root that points to the old anon_vma and locks it. As a result, thread B can call anon_vma_lock_write() with the old root, and call anon_vma_unlock_write() with the new root, leading to an anon_vma will never be unlocked, and another anon_vma couldn't be locked anymore (its count is dropped from 0 to -1 due to wrong unlock). To fix it, change the plain store `vma->anon_vma = anon_vma` to store release, so that the fields of anon_vma are visible before anon_vma is published to vma->anon_vma. At read side, the load of anon_vma and anon_vma->root have address dependency. According to Documentation/memory-barriers.txt and some investigations, only Alpha needs address-dependency barriers and it has been handled by READ_ONCE() in reusable_anon_vma(). We reproduced this issue in v5.10 with KSM enabled. The kernel doesn't merge commit cf7e7a3503df ("mm: prevent KSM from breaking VMA merging for new VMAs"), so there are many adjacent VMAs that aren't merged but are compatible for anon_vma. Without this fix, our production environment could reproduce this issue about 2-5 times each month. After adding a smp_mb() before anon_vma_lock_write(anon_vma) in __anon_vma_prepare(), which is different to this patch, this issue hasn't been reproduced for one month. Link: https://lore.kernel.org/20260908122924.554373-1-tujinjiang@huawei.com Fixes: 5c341ee1dfc8 ("mm: track the root (oldest) anon_vma") Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Reviewed-by: Lance Yang <lance.yang(a)linux.dev> Reviewed-by: Lorenzo Stoakes (ARM) <ljs(a)kernel.org> Acked-by: David Hildenbrand (Arm) <david(a)kernel.org> Acked-by: Vlastimil Babka (SUSE) <vbabka(a)kernel.org> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Harry Yoo <harry(a)kernel.org> Cc: Hiroyouki Kamezawa <kamezawa.hiroyu(a)jp.fujitsu.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com> Cc: Larry Woodman <lwoodman(a)redhat.com> Cc: Liam R. Howlett <liam(a)infradead.org> Cc: Nanyong Sun <sunnanyong(a)huawei.com> Cc: Rik van Riel <riel(a)surriel.com> Cc: <stable(a)vger.kernel.org> Conflicts: mm/rmap.c mm/mmap.c mm/vma.c [Context conflicts.] Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com> --- mm/mmap.c | 7 +++++++ mm/rmap.c | 6 +++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index c0262befcaae..604c0c877c5c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1300,6 +1300,13 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct * * acceptable for merging, so we can do all of this optimistically. But * we do that READ_ONCE() to make sure that we never re-load the pointer. * + * The READ_ONCE() establishes an address dependency between anon_vma and + * any access to its fields, which pairs with the assignment to + * vma->anon_vma performed with release semantics in __anon_vma_prepare(). + * + * This is especially important as anon_vma's are SLAB_TYPESAFE_BY_RCU so + * accessing an uninitialised anon_vma's fields may result in a UAF. + * * IOW: that the "list_is_singular()" test on the anon_vma_chain only * matters for the 'stable anon_vma' case (ie the thing we want to avoid * is to return an anon_vma that is "complex" due to having gone through diff --git a/mm/rmap.c b/mm/rmap.c index 150803a7ffb5..fb07b2b32a91 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -206,7 +206,11 @@ int __anon_vma_prepare(struct vm_area_struct *vma) /* page_table_lock to protect against threads */ spin_lock(&mm->page_table_lock); if (likely(!vma->anon_vma)) { - vma->anon_vma = anon_vma; + /* + * Make anon_vma fields visible before anon_vma is published. + * Paired with an address dependency in reusable_anon_vma(). + */ + smp_store_release(&vma->anon_vma, anon_vma); anon_vma_chain_link(vma, avc, anon_vma); anon_vma->num_active_vmas++; allocated = NULL; -- 2.43.0

1 0

[PATCH OLK-6.6 0/2] CVE-2026-89713
by Yang Erkun 24 Sep '26

24 Sep '26

Chuck Lever (1): NFSD: check truncate permission under inode lock NeilBrown (1): nfsd: Pass 'cred' instead of 'rqstp' to some functions. fs/nfsd/auth.c | 14 +++++++------- fs/nfsd/auth.h | 2 +- fs/nfsd/export.h | 3 ++- fs/nfsd/nfs4state.c | 3 ++- fs/nfsd/nfsfh.c | 6 +++--- fs/nfsd/nfsproc.c | 9 +++++---- fs/nfsd/vfs.c | 45 +++++++++++++++++++++++++++------------------ fs/nfsd/vfs.h | 4 ++-- 8 files changed, 49 insertions(+), 37 deletions(-) -- 2.52.0

2 3

[PATCH OLK-6.6] scsi: qla2xxx: Zero SFP DMA buffer in FRU/I2C bsg handlers
by Pan Taixi 24 Sep '26

24 Sep '26

From: Nilesh Javali <njavali(a)marvell.com> stable inclusion from stable-v6.6.157 commit 84bde5ce4038d9ad811e5c994305bbfcbd7a9f79 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19080 CVE: CVE-2026-89865 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit b47d4a1547d9ef21b2e9d1a739fe2204d4be05dc upstream. The FRU and I2C bsg handlers stage their transfer in a DMA_POOL_SIZE (256-byte) bounce buffer obtained from dma_pool_alloc(), which does not zero the allocation. They initialize only a few leading bytes before handing the buffer to qla2x00_write_sfp(). qla2x00_write_sfp() can override the transfer length with a user-supplied value: if (len == 1) opt |= BIT_0; if (opt & BIT_0) len = *sfp; *sfp is the first byte of the (user-controlled) payload, so len can grow up to 255. The device then DMA-reads len bytes from the 256-byte pool buffer. Since only a small prefix was written (e.g. MAX_FRU_SIZE == 36 bytes for a FRU version, one byte for a FRU status register), the hardware reads past the initialized region and writes up to ~219 bytes of stale DMA-pool heap memory to the device flash. Allocate the buffer with dma_pool_zalloc() in all five FRU/I2C handlers so any bytes beyond the initialized data are zero rather than stale heap contents. Fixes: 697a4bc69159 ("[SCSI] qla2xxx: Provide method for updating I2C attached VPD.") Fixes: 9ebb5d9c69f1 ("[SCSI] qla2xxx: Add I2C BSG interface.") Cc: stable(a)vger.kernel.org Reported-by: Sashiko <sashiko-dev(a)google.com> Signed-off-by: Nilesh Javali <njavali(a)marvell.com> Link: https://patch.msgid.link/20260730155838.2119230-32-njavali@marvell.com Signed-off-by: Martin K. Petersen (Oracle) <mkp(a)kernel.org> Conflicts: drivers/scsi/qla2xxx/qla_bsg.c [Context conflicts due to aa51b8115a6a ("scsi: qla2xxx: Zero-init bsg stack buffers to avoid info leak")] Signed-off-by: Pan Taixi <pantaixi1(a)huawei.com> --- drivers/scsi/qla2xxx/qla_bsg.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/qla2xxx/qla_bsg.c b/drivers/scsi/qla2xxx/qla_bsg.c index b372bcb9ba04..55e98f39ed16 100644 --- a/drivers/scsi/qla2xxx/qla_bsg.c +++ b/drivers/scsi/qla2xxx/qla_bsg.c @@ -1563,11 +1563,11 @@ qla2x00_update_fru_versions(struct bsg_job *bsg_job) uint8_t bsg[DMA_POOL_SIZE] = {}; struct qla_image_version_list *list = (void *)bsg; struct qla_image_version *image; uint32_t count; dma_addr_t sfp_dma; - void *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); + void *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); if (!sfp) { bsg_reply->reply_data.vendor_reply.vendor_rsp[0] = EXT_STATUS_NO_MEMORY; goto done; @@ -1614,11 +1614,11 @@ qla2x00_read_fru_status(struct bsg_job *bsg_job) struct qla_hw_data *ha = vha->hw; int rval = 0; uint8_t bsg[DMA_POOL_SIZE] = {}; struct qla_status_reg *sr = (void *)bsg; dma_addr_t sfp_dma; - uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); + uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); if (!sfp) { bsg_reply->reply_data.vendor_reply.vendor_rsp[0] = EXT_STATUS_NO_MEMORY; goto done; @@ -1665,11 +1665,11 @@ qla2x00_write_fru_status(struct bsg_job *bsg_job) struct qla_hw_data *ha = vha->hw; int rval = 0; uint8_t bsg[DMA_POOL_SIZE] = {}; struct qla_status_reg *sr = (void *)bsg; dma_addr_t sfp_dma; - uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); + uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); if (!sfp) { bsg_reply->reply_data.vendor_reply.vendor_rsp[0] = EXT_STATUS_NO_MEMORY; goto done; @@ -1712,11 +1712,11 @@ qla2x00_write_i2c(struct bsg_job *bsg_job) struct qla_hw_data *ha = vha->hw; int rval = 0; uint8_t bsg[DMA_POOL_SIZE] = {}; struct qla_i2c_access *i2c = (void *)bsg; dma_addr_t sfp_dma; - uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); + uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); if (!sfp) { bsg_reply->reply_data.vendor_reply.vendor_rsp[0] = EXT_STATUS_NO_MEMORY; goto done; @@ -1758,11 +1758,11 @@ qla2x00_read_i2c(struct bsg_job *bsg_job) struct qla_hw_data *ha = vha->hw; int rval = 0; uint8_t bsg[DMA_POOL_SIZE] = {}; struct qla_i2c_access *i2c = (void *)bsg; dma_addr_t sfp_dma; - uint8_t *sfp = dma_pool_alloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); + uint8_t *sfp = dma_pool_zalloc(ha->s_dma_pool, GFP_KERNEL, &sfp_dma); if (!sfp) { bsg_reply->reply_data.vendor_reply.vendor_rsp[0] = EXT_STATUS_NO_MEMORY; goto done; -- 2.34.1

2 1

[PATCH OLK-6.6] [Backport] media: cec: core: Fix kmemleak due to missed rc_free_device() call
by Tang Hui 24 Sep '26

24 Sep '26

From: Jonas Karlman <jonas(a)kwiboo.se> stable inclusion from stable-v6.6.157 commit 954ee95a03b4d31d4505591bfaba02c24b75776b category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19091 CVE: CVE-2026-89900 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a24ba0653f7154e671dc8d2bf64682ab2d042792 upstream. The commit dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks") removed the implicit call to rc_free_device() from rc_unregister_device(). However, the commit missed to remove the NULL assignment of adap->rc that is now causing rc_free_device() to never be called on an allocated rc device. kmemleak reports following after e.g. dw-hdmi unbind: unreferenced object 0xffff00010ac10000 (size 4096): comm "kworker/u16:1", pid 39, jiffies 4294897739 hex dump (first 32 bytes): 20 23 4b 0a 01 00 ff ff 08 00 c1 0a 01 00 ff ff #K............. 08 00 c1 0a 01 00 ff ff 00 00 00 00 00 00 00 00 ................ backtrace (crc e11baccc): kmemleak_alloc+0x38/0x44 __kmalloc_cache_noprof+0x4a8/0x5e0 rc_allocate_device+0x48/0x2a0 cec_allocate_adapter+0x3ac/0x800 dw_hdmi_cec_probe+0x264/0x634 platform_probe+0xc0/0x188 really_probe+0x4a4/0x8e0 __driver_probe_device+0x2f8/0x440 driver_probe_device+0x60/0x160 __device_attach_driver+0x1a0/0x2a0 bus_for_each_drv+0x100/0x1a0 __device_attach+0x174/0x350 device_initial_probe+0x90/0xb0 bus_probe_device+0x4c/0x120 device_add+0xdec/0x116c platform_device_add+0x354/0x598 Remove the assignment of adap->rc to NULL to let cec_delete_adapter() free the allocated rc device after last user of the cec device exits to fix the kmemleak. Fixes: dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks") Cc: stable(a)vger.kernel.org Signed-off-by: Jonas Karlman <jonas(a)kwiboo.se> Signed-off-by: Hans Verkuil <hverkuil+cisco(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Co-authored-by: BackportAgent(a)deepseek-v4.1-flash Signed-off-by: Hulk Robot <hulkrobot(a)huawei.com> Signed-off-by: Tang Hui <tanghui20(a)huawei.com> --- drivers/media/cec/core/cec-core.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/media/cec/core/cec-core.c b/drivers/media/cec/core/cec-core.c index 74dff5f8d3365..db07bc64cd672 100644 --- a/drivers/media/cec/core/cec-core.c +++ b/drivers/media/cec/core/cec-core.c @@ -399,9 +399,7 @@ void cec_unregister_adapter(struct cec_adapter *adap) return; #ifdef CONFIG_MEDIA_CEC_RC - /* Note: rc_unregister also calls rc_free */ rc_unregister_device(adap->rc); - adap->rc = NULL; #endif debugfs_remove_recursive(adap->cec_dir); #ifdef CONFIG_CEC_NOTIFIER -- 2.34.1

2 1

[PATCH OLK-6.6] fs: fix user path of nested backing files
by Yang Erkun 24 Sep '26

24 Sep '26

From: Baokun Li <libaokun(a)linux.alibaba.com> mainline inclusion from mainline-v7.3-rc1 commit f2381b546e7e6a35c9fcee0d0ccb6c042a9aeb5d category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19027 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- backing_file_open() derives the path to be stored in the new backing file from user_file->f_path. This is incorrect when user_file itself is a backing file, which is the case for nested stacking filesystems, e.g. overlayfs mounts where the lowerdir of one overlayfs is the merged directory of another. Since commit def3ae83da02 ("fs: store real path instead of fake path in backing file f_path") the f_path of a backing file holds the real path of the intermediate layer, not the path that the user opened. Commit 924577e4f6ca ("ovl: Fix nested backing file paths") fixed this for such configurations by passing file_user_path() from ovl_open_realfile(). However, commit 6af36aeb147a ("lsm: add backing_file LSM hooks") changed the first argument of backing_file_open() from the user path back to the user file and derived the path from user_file->f_path again, silently re-introducing the problem. As a result, files mapped through a nested overlayfs show the wrong path in /proc/<pid>/maps and in perf/ftrace mmap records. For example, with two nested overlayfs mounts: mkdir -p /ovl/{lower,upper,work,merged} /ovl/nested echo hello > /ovl/lower/foo mount -t overlay overlay \ -o lowerdir=/ovl/lower,upperdir=/ovl/upper,workdir=/ovl/work \ /ovl/merged # at least two lowerdirs are needed when upperdir is nonexistent mount -t overlay overlay \ -o lowerdir=/ovl/merged:/ovl/lower /ovl/nested mapping /ovl/nested/foo shows a disconnected path instead of the user path: # readlink /proc/self/fd/3 /ovl/nested/foo # grep foo /proc/self/maps 7f6e2c100000-7f6e2c101000 r--s 00000000 00:24 15813027 /foo The bogus path is derived from the f_path of the intermediate backing file, whose mount is a private clone that d_path() cannot resolve. Fix this by using file_user_path(), which returns the outermost user-visible path for backing files and falls back to &user_file->f_path for regular files. This restores the behavior of commit 924577e4f6ca ("ovl: Fix nested backing file paths") for overlayfs and also fixes the same problem for the other backing_file_open() callers, fuse passthrough and erofs ishare, when their user file is itself a backing file. backing_tmpfile_open() has the same pattern but is not affected: it is only called by ovl_create_tmpfile() for the upper layer, and another overlayfs is rejected as upperdir by the DCACHE_OP_REAL check in ovl_mount_dir_check(), so its user_file can never be a backing file. Fixes: 6af36aeb147a ("lsm: add backing_file LSM hooks") Cc: stable(a)vger.kernel.org Signed-off-by: Baokun Li <libaokun(a)linux.alibaba.com> Link: https://patch.msgid.link/20260804034204.3487077-1-libaokun@linux.alibaba.com Tested-by: Paul Moore <paul(a)paul-moore.com> Signed-off-by: Christian Brauner (Amutable) <brauner(a)kernel.org> Conflicts: fs/backing-file.c [Context conflicts] Signed-off-by: Yang Erkun <yangerkun(a)huawei.com> --- fs/backing-file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/backing-file.c b/fs/backing-file.c index d363f47b3236..3a35b0224e32 100644 --- a/fs/backing-file.c +++ b/fs/backing-file.c @@ -34,7 +34,7 @@ struct file *backing_file_open(const struct file *user_file, int flags, const struct path *real_path, const struct cred *cred) { - const struct path *user_path = &user_file->f_path; + const struct path *user_path = file_user_path(user_file); struct file *f; int error; -- 2.52.0

2 1

[PATCH OLK-5.10] fs: fix user path of nested backing files
by Yang Erkun 24 Sep '26

24 Sep '26

From: Baokun Li <libaokun(a)linux.alibaba.com> mainline inclusion from mainline-v7.3-rc1 commit f2381b546e7e6a35c9fcee0d0ccb6c042a9aeb5d category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19027 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- backing_file_open() derives the path to be stored in the new backing file from user_file->f_path. This is incorrect when user_file itself is a backing file, which is the case for nested stacking filesystems, e.g. overlayfs mounts where the lowerdir of one overlayfs is the merged directory of another. Since commit def3ae83da02 ("fs: store real path instead of fake path in backing file f_path") the f_path of a backing file holds the real path of the intermediate layer, not the path that the user opened. Commit 924577e4f6ca ("ovl: Fix nested backing file paths") fixed this for such configurations by passing file_user_path() from ovl_open_realfile(). However, commit 6af36aeb147a ("lsm: add backing_file LSM hooks") changed the first argument of backing_file_open() from the user path back to the user file and derived the path from user_file->f_path again, silently re-introducing the problem. As a result, files mapped through a nested overlayfs show the wrong path in /proc/<pid>/maps and in perf/ftrace mmap records. For example, with two nested overlayfs mounts: mkdir -p /ovl/{lower,upper,work,merged} /ovl/nested echo hello > /ovl/lower/foo mount -t overlay overlay \ -o lowerdir=/ovl/lower,upperdir=/ovl/upper,workdir=/ovl/work \ /ovl/merged # at least two lowerdirs are needed when upperdir is nonexistent mount -t overlay overlay \ -o lowerdir=/ovl/merged:/ovl/lower /ovl/nested mapping /ovl/nested/foo shows a disconnected path instead of the user path: # readlink /proc/self/fd/3 /ovl/nested/foo # grep foo /proc/self/maps 7f6e2c100000-7f6e2c101000 r--s 00000000 00:24 15813027 /foo The bogus path is derived from the f_path of the intermediate backing file, whose mount is a private clone that d_path() cannot resolve. Fix this by using file_user_path(), which returns the outermost user-visible path for backing files and falls back to &user_file->f_path for regular files. This restores the behavior of commit 924577e4f6ca ("ovl: Fix nested backing file paths") for overlayfs and also fixes the same problem for the other backing_file_open() callers, fuse passthrough and erofs ishare, when their user file is itself a backing file. backing_tmpfile_open() has the same pattern but is not affected: it is only called by ovl_create_tmpfile() for the upper layer, and another overlayfs is rejected as upperdir by the DCACHE_OP_REAL check in ovl_mount_dir_check(), so its user_file can never be a backing file. Fixes: 6af36aeb147a ("lsm: add backing_file LSM hooks") Cc: stable(a)vger.kernel.org Signed-off-by: Baokun Li <libaokun(a)linux.alibaba.com> Link: https://patch.msgid.link/20260804034204.3487077-1-libaokun@linux.alibaba.com Tested-by: Paul Moore <paul(a)paul-moore.com> Signed-off-by: Christian Brauner (Amutable) <brauner(a)kernel.org> Conflicts: fs/open.c [Upstream commit f2381b546e7e moved backing_file_open() into fs/backing-file.c, which does not exist in this tree; backing_file_open() still lives in fs/open.c here, so the same one-line change (use file_user_path() instead of user_file->f_path) was applied there.] Signed-off-by: Yang Erkun <yangerkun(a)huawei.com> --- fs/open.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index 44ffd83872d0..2efd2b15c48f 100644 --- a/fs/open.c +++ b/fs/open.c @@ -988,7 +988,7 @@ struct file *backing_file_open(const struct file *user_file, int flags, const struct path *real_path, const struct cred *cred) { - const struct path *user_path = &user_file->f_path; + const struct path *user_path = file_user_path(user_file); struct file *f; int error; -- 2.52.0

2 1

[PATCH OLK-6.6] bpf: Invalidate RCU pointers after final spin unlock
by Pu Lehui 24 Sep '26

24 Sep '26

From: Ning Ding <dingning04(a)gmail.com> mainline inclusion from mainline-v7.3-rc1 commit 180c7000712db77063b3a26f4c97e7dd9038f449 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19478 CVE: CVE-2026-90317 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- In a sleepable BPF program, a spin lock can provide the only RCU protection for a kptr. The final bpf_spin_unlock() ends that protection, but the verifier leaves the pointer valid. Another CPU can then free the object before the pointer is used. A capability-limited runtime PoC triggered a task_struct use-after-free in __bpf_get_task_stack(). Record whether the program is in an RCU-protected context before releasing the lock. Invalidate RCU-protected pointers only when the unlock leaves the final such context. This preserves valid pointers in non-sleepable programs and inside an explicit RCU read-side section. Fixes: 5861d1e8dbc4 ("bpf: Allow bpf_spin_{lock,unlock} in sleepable progs") Assisted-by: Codex:gpt-5.6-sol Assisted-by: ChatGPT:GPT-5.6-Pro Signed-off-by: Ning Ding <dingning04(a)gmail.com> Link: https://lore.kernel.org/bpf/20260803112615.3362122-2-dingning04@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor(a)gmail.com> Conflicts: kernel/bpf/verifier.c [no invalidate_rcu_protected_refs and release_lock_state] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/bpf/verifier.c | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index fc50caec35be..f0a67a9f8d1a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -198,6 +198,7 @@ struct bpf_verifier_stack_elem { static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx); static int release_reference(struct bpf_verifier_env *env, int ref_obj_id); static void invalidate_non_owning_refs(struct bpf_verifier_env *env); +static void invalidate_rcu_protected_refs(struct bpf_verifier_env *env); static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env); static int ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state *reg); @@ -7651,6 +7652,7 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, cur->active_lock.ptr = btf; cur->active_lock.id = reg->id; } else { + bool was_in_rcu_cs; void *ptr; if (map) @@ -7668,10 +7670,15 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, return -EINVAL; } + was_in_rcu_cs = in_rcu_cs(env); + invalidate_non_owning_refs(env); cur->active_lock.ptr = NULL; cur->active_lock.id = 0; + + if (was_in_rcu_cs && !in_rcu_cs(env)) + invalidate_rcu_protected_refs(env); } return 0; } @@ -9389,6 +9396,20 @@ static void invalidate_non_owning_refs(struct bpf_verifier_env *env) })); } +static void invalidate_rcu_protected_refs(struct bpf_verifier_env *env) +{ + struct bpf_func_state *state; + struct bpf_reg_state *reg; + u32 clear_mask = (1 << STACK_SPILL) | (1 << STACK_ITER); + + bpf_for_each_reg_in_vstate_mask(env->cur_state, state, reg, clear_mask, ({ + if (reg->type & MEM_RCU) { + reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL); + reg->type |= PTR_UNTRUSTED; + } + })); +} + static void clear_caller_saved_regs(struct bpf_verifier_env *env, struct bpf_reg_state *regs) { @@ -12155,10 +12176,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta); if (env->cur_state->active_rcu_lock) { - struct bpf_func_state *state; - struct bpf_reg_state *reg; - u32 clear_mask = (1 << STACK_SPILL) | (1 << STACK_ITER); - if (in_rbtree_lock_required_cb(env) && (rcu_lock || rcu_unlock)) { verbose(env, "Calling bpf_rcu_read_{lock,unlock} in unnecessary rbtree callback\n"); return -EACCES; @@ -12168,12 +12185,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, verbose(env, "nested rcu read lock (kernel function %s)\n", func_name); return -EINVAL; } else if (rcu_unlock) { - bpf_for_each_reg_in_vstate_mask(env->cur_state, state, reg, clear_mask, ({ - if (reg->type & MEM_RCU) { - reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL); - reg->type |= PTR_UNTRUSTED; - } - })); + invalidate_rcu_protected_refs(env); env->cur_state->active_rcu_lock = false; } else if (sleepable) { verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name); -- 2.34.1

2 1

[PATCH openEuler-1.0-LTS] openvswitch: fix GSO userspace truncation underflow
by Yi Yang 24 Sep '26

24 Sep '26

From: Kyle Zeng <kylebot(a)openai.com> stable inclusion from stable-v5.10.265 commit 50a6a85f3d6b1d22d8436848606cdef5d2c490b4 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16932 CVE: CVE-2026-68123 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 4032f8ed10fcb84d41c508dfb04be96589f78dfe ] OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb length in OVS_CB(skb)->cutlen. When a later userspace action segments a GSO skb, queue_gso_packets() reuses that delta for each smaller segment. A segment can then reach queue_userspace_packet() with cutlen greater than skb->len, underflowing the length passed to skb_zerocopy(). Store the maximum preserved length instead and bound each consumer against the current skb length. Use U32_MAX as the no-truncation sentinel so the value remains valid if skb geometry changes before a consumer handles it. Fixes: f2a4d086ed4c ("openvswitch: Add packet truncation support.") Cc: stable(a)vger.kernel.org Assisted-by: Codex:gpt-5.5 Signed-off-by: Kyle Zeng <kylebot(a)openai.com> Reviewed-by: Ilya Maximets <i.maximets(a)ovn.org> Reviewed-by: Aaron Conole <aconole(a)redhat.com> Link: https://patch.msgid.link/20260707221635.27489-1-kylebot@openai.com Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> [5.10.y supports neither OVS_ACTION_ATTR_PSAMPLE nor OVS drop reasons] Signed-off-by: Ilya Maximets <i.maximets(a)ovn.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Conflicts: net/openvswitch/actions.c [The max function requires that the types be the same.] net/openvswitch/datapath.c [Context conflicts.] Signed-off-by: Yi Yang <yiyang13(a)huawei.com> --- net/openvswitch/actions.c | 16 ++++++---------- net/openvswitch/datapath.c | 25 ++++++++++++++----------- net/openvswitch/datapath.h | 2 +- net/openvswitch/vport.c | 2 +- 4 files changed, 22 insertions(+), 23 deletions(-) diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 7ac5f75e06a9..669578e423f9 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -949,12 +949,9 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port, u16 mru = OVS_CB(skb)->mru; u32 cutlen = OVS_CB(skb)->cutlen; - if (unlikely(cutlen > 0)) { - if (skb->len - cutlen > ovs_mac_header_len(key)) - pskb_trim(skb, skb->len - cutlen); - else - pskb_trim(skb, ovs_mac_header_len(key)); - } + if (unlikely(cutlen < skb->len)) + pskb_trim(skb, max_t(u32, cutlen, + ovs_mac_header_len(key))); if (likely(!mru || (skb->len <= mru + vport->dev->hard_header_len))) { @@ -1237,22 +1234,21 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, clone = skb_clone(skb, GFP_ATOMIC); if (clone) do_output(dp, clone, port, key); - OVS_CB(skb)->cutlen = 0; + OVS_CB(skb)->cutlen = U32_MAX; break; } case OVS_ACTION_ATTR_TRUNC: { struct ovs_action_trunc *trunc = nla_data(a); - if (skb->len > trunc->max_len) - OVS_CB(skb)->cutlen = skb->len - trunc->max_len; + OVS_CB(skb)->cutlen = trunc->max_len; break; } case OVS_ACTION_ATTR_USERSPACE: output_userspace(dp, skb, key, a, attr, len, OVS_CB(skb)->cutlen); - OVS_CB(skb)->cutlen = 0; + OVS_CB(skb)->cutlen = U32_MAX; break; case OVS_ACTION_ATTR_HASH: diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index bd00e63603ca..1aeeb18c8812 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -248,7 +248,7 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key) upcall.cmd = OVS_PACKET_CMD_MISS; upcall.portid = ovs_vport_find_upcall_portid(p, skb); upcall.mru = OVS_CB(skb)->mru; - error = ovs_dp_upcall(dp, skb, key, &upcall, 0); + error = ovs_dp_upcall(dp, skb, key, &upcall, U32_MAX); if (unlikely(error)) kfree_skb(skb); else @@ -399,7 +399,8 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, struct sk_buff *nskb = NULL; struct sk_buff *user_skb = NULL; /* to be queued to userspace */ struct nlattr *nla; - size_t len; + size_t msg_size; + size_t skb_len; unsigned int hlen; int err, dp_ifindex; @@ -419,7 +420,8 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, skb = nskb; } - if (nla_attr_size(skb->len) > USHRT_MAX) { + skb_len = min(skb->len, cutlen); + if (nla_attr_size(skb_len) > USHRT_MAX) { err = -EFBIG; goto out; } @@ -434,13 +436,13 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, * padding logic. Only perform zerocopy if padding is not required. */ if (dp->user_features & OVS_DP_F_UNALIGNED) - hlen = skb_zerocopy_headlen(skb); + hlen = min(skb_zerocopy_headlen(skb), cutlen); else - hlen = skb->len; + hlen = skb_len; - len = upcall_msg_size(upcall_info, hlen - cutlen, - OVS_CB(skb)->acts_origlen); - user_skb = genlmsg_new(len, GFP_ATOMIC); + msg_size = upcall_msg_size(upcall_info, hlen, + OVS_CB(skb)->acts_origlen); + user_skb = genlmsg_new(msg_size, GFP_ATOMIC); if (!user_skb) { err = -ENOMEM; goto out; @@ -503,7 +505,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, } /* Add OVS_PACKET_ATTR_LEN when packet is truncated */ - if (cutlen > 0) { + if (skb_len < skb->len) { if (nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, skb->len)) { err = -ENOBUFS; @@ -518,9 +520,9 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, err = -ENOBUFS; goto out; } - nla->nla_len = nla_attr_size(skb->len - cutlen); + nla->nla_len = nla_attr_size(skb_len); - err = skb_zerocopy(user_skb, skb, skb->len - cutlen, hlen); + err = skb_zerocopy(user_skb, skb, skb_len, hlen); if (err) goto out; @@ -575,6 +577,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info) packet->ignore_df = 1; } OVS_CB(packet)->mru = mru; + OVS_CB(packet)->cutlen = U32_MAX; /* Build an sw_flow for sending this packet. */ flow = ovs_flow_alloc(); diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h index c9eb267c6f7e..9192c9970cc3 100644 --- a/net/openvswitch/datapath.h +++ b/net/openvswitch/datapath.h @@ -105,7 +105,7 @@ struct datapath { * @mru: The maximum received fragement size; 0 if the packet is not * fragmented. * @acts_origlen: The netlink size of the flow actions applied to this skb. - * @cutlen: The number of bytes from the packet end to be removed. + * @cutlen: The number of bytes in the packet to preserve on output. */ struct ovs_skb_cb { struct vport *input_vport; diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c index 5541f4c9a0a1..586428d2015d 100644 --- a/net/openvswitch/vport.c +++ b/net/openvswitch/vport.c @@ -447,7 +447,7 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb, OVS_CB(skb)->input_vport = vport; OVS_CB(skb)->mru = 0; - OVS_CB(skb)->cutlen = 0; + OVS_CB(skb)->cutlen = U32_MAX; if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) { u32 mark; -- 2.25.1

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