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[PATCH v5 1/1] mm/rmap: fix soft-dirty and uffd-wp bit loss when remapping zero-filled mTHP subpage to shared zeropage

by Lance Yang

From: Lance Yang <lance.yang(a)linux.dev> When splitting an mTHP and replacing a zero-filled subpage with the shared zeropage, try_to_map_unused_to_zeropage() currently drops several important PTE bits. For userspace tools like CRIU, which rely on the soft-dirty mechanism for incremental snapshots, losing the soft-dirty bit means modified pages are missed, leading to inconsistent memory state after restore. As pointed out by David, the more critical uffd-wp bit is also dropped. This breaks the userfaultfd write-protection mechanism, causing writes to be silently missed by monitoring applications, which can lead to data corruption. Preserve both the soft-dirty and uffd-wp bits from the old PTE when creating the new zeropage mapping to ensure they are correctly tracked. Cc: <stable(a)vger.kernel.org> Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") Suggested-by: David Hildenbrand <david(a)redhat.com> Suggested-by: Dev Jain <dev.jain(a)arm.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Dev Jain <dev.jain(a)arm.com> Signed-off-by: Lance Yang <lance.yang(a)linux.dev> --- v4 -> v5: - Move ptep_get() call after the !pvmw.pte check, which handles PMD-mapped THP migration entries. - https://lore.kernel.org/linux-mm/20250930071053.36158-1-lance.yang@linux.de… v3 -> v4: - Minor formatting tweak in try_to_map_unused_to_zeropage() function signature (per David and Dev) - Collect Reviewed-by from Dev - thanks! - https://lore.kernel.org/linux-mm/20250930060557.85133-1-lance.yang@linux.de… v2 -> v3: - ptep_get() gets called only once per iteration (per Dev) - https://lore.kernel.org/linux-mm/20250930043351.34927-1-lance.yang@linux.de… v1 -> v2: - Avoid calling ptep_get() multiple times (per Dev) - Double-check the uffd-wp bit (per David) - Collect Acked-by from David - thanks! - https://lore.kernel.org/linux-mm/20250928044855.76359-1-lance.yang@linux.de… mm/migrate.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index ce83c2c3c287..e3065c9edb55 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -296,8 +296,7 @@ bool isolate_folio_to_list(struct folio *folio, struct list_head *list) } static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, - struct folio *folio, - unsigned long idx) + struct folio *folio, pte_t old_pte, unsigned long idx) { struct page *page = folio_page(folio, idx); pte_t newpte; @@ -306,7 +305,7 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, return false; VM_BUG_ON_PAGE(!PageAnon(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(pte_present(ptep_get(pvmw->pte)), page); + VM_BUG_ON_PAGE(pte_present(old_pte), page); if (folio_test_mlocked(folio) || (pvmw->vma->vm_flags & VM_LOCKED) || mm_forbids_zeropage(pvmw->vma->vm_mm)) @@ -322,6 +321,12 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address), pvmw->vma->vm_page_prot)); + + if (pte_swp_soft_dirty(old_pte)) + newpte = pte_mksoft_dirty(newpte); + if (pte_swp_uffd_wp(old_pte)) + newpte = pte_mkuffd_wp(newpte); + set_pte_at(pvmw->vma->vm_mm, pvmw->address, pvmw->pte, newpte); dec_mm_counter(pvmw->vma->vm_mm, mm_counter(folio)); @@ -364,13 +369,13 @@ static bool remove_migration_pte(struct folio *folio, continue; } #endif + old_pte = ptep_get(pvmw.pte); if (rmap_walk_arg->map_unused_to_zeropage && - try_to_map_unused_to_zeropage(&pvmw, folio, idx)) + try_to_map_unused_to_zeropage(&pvmw, folio, old_pte, idx)) continue; folio_get(folio); pte = mk_pte(new, READ_ONCE(vma->vm_page_prot)); - old_pte = ptep_get(pvmw.pte); entry = pte_to_swp_entry(old_pte); if (!is_migration_entry_young(entry)) -- 2.49.0

3 weeks, 1 day

5
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[PATCH net 02/10] can: gs_usb: gs_make_candev(): populate net_device->dev_port

by Marc Kleine-Budde

From: Celeste Liu <uwu(a)coelacanthus.name> The gs_usb driver supports USB devices with more than 1 CAN channel. In old kernel before 3.15, it uses net_device->dev_id to distinguish different channel in userspace, which was done in commit acff76fa45b4 ("can: gs_usb: gs_make_candev(): set netdev->dev_id"). But since 3.15, the correct way is populating net_device->dev_port. And according to documentation, if network device support multiple interface, lack of net_device->dev_port SHALL be treated as a bug. Fixes: acff76fa45b4 ("can: gs_usb: gs_make_candev(): set netdev->dev_id") Cc: stable(a)vger.kernel.org Signed-off-by: Celeste Liu <uwu(a)coelacanthus.name> Link: https://patch.msgid.link/20250930-gs-usb-populate-net_device-dev_port-v1-1-… Signed-off-by: Marc Kleine-Budde <mkl(a)pengutronix.de> --- drivers/net/can/usb/gs_usb.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index 9fb4cbbd6d6d..69b8d6da651b 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -1245,6 +1245,7 @@ static struct gs_can *gs_make_candev(unsigned int channel, netdev->flags |= IFF_ECHO; /* we support full roundtrip echo */ netdev->dev_id = channel; + netdev->dev_port = channel; /* dev setup */ strcpy(dev->bt_const.name, KBUILD_MODNAME); -- 2.51.0

3 weeks, 1 day

1
0
0 0

FAILED: patch "[PATCH] mm/ksm: fix incorrect KSM counter handling in mm_struct" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 4d6fc29f36341d7795db1d1819b4c15fe9be7b23 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101358-bucket-cadet-c4d4@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4d6fc29f36341d7795db1d1819b4c15fe9be7b23 Mon Sep 17 00:00:00 2001 From: Donet Tom <donettom(a)linux.ibm.com> Date: Wed, 24 Sep 2025 00:16:59 +0530 Subject: [PATCH] mm/ksm: fix incorrect KSM counter handling in mm_struct during fork Patch series "mm/ksm: Fix incorrect accounting of KSM counters during fork", v3. The first patch in this series fixes the incorrect accounting of KSM counters such as ksm_merging_pages, ksm_rmap_items, and the global ksm_zero_pages during fork. The following patch add a selftest to verify the ksm_merging_pages counter was updated correctly during fork. Test Results ============ Without the first patch ----------------------- # [RUN] test_fork_ksm_merging_page_count not ok 10 ksm_merging_page in child: 32 With the first patch -------------------- # [RUN] test_fork_ksm_merging_page_count ok 10 ksm_merging_pages is not inherited after fork This patch (of 2): Currently, the KSM-related counters in `mm_struct`, such as `ksm_merging_pages`, `ksm_rmap_items`, and `ksm_zero_pages`, are inherited by the child process during fork. This results in inconsistent accounting. When a process uses KSM, identical pages are merged and an rmap item is created for each merged page. The `ksm_merging_pages` and `ksm_rmap_items` counters are updated accordingly. However, after a fork, these counters are copied to the child while the corresponding rmap items are not. As a result, when the child later triggers an unmerge, there are no rmap items present in the child, so the counters remain stale, leading to incorrect accounting. A similar issue exists with `ksm_zero_pages`, which maintains both a global counter and a per-process counter. During fork, the per-process counter is inherited by the child, but the global counter is not incremented. Since the child also references zero pages, the global counter should be updated as well. Otherwise, during zero-page unmerge, both the global and per-process counters are decremented, causing the global counter to become inconsistent. To fix this, ksm_merging_pages and ksm_rmap_items are reset to 0 during fork, and the global ksm_zero_pages counter is updated with the per-process ksm_zero_pages value inherited by the child. This ensures that KSM statistics remain accurate and reflect the activity of each process correctly. Link: https://lkml.kernel.org/r/cover.1758648700.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/7b9870eb67ccc0d79593940d9dbd4a0b39b5d396.17586487… Fixes: 7609385337a4 ("ksm: count ksm merging pages for each process") Fixes: cb4df4cae4f2 ("ksm: count allocated ksm rmap_items for each process") Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Signed-off-by: Donet Tom <donettom(a)linux.ibm.com> Reviewed-by: Chengming Zhou <chengming.zhou(a)linux.dev> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Aboorva Devarajan <aboorvad(a)linux.ibm.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Donet Tom <donettom(a)linux.ibm.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list(a)gmail.com> Cc: Wei Yang <richard.weiyang(a)gmail.com> Cc: xu xin <xu.xin16(a)zte.com.cn> Cc: <stable(a)vger.kernel.org> [6.6+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 22e67ca7cba3..067538fc4d58 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -56,8 +56,14 @@ static inline long mm_ksm_zero_pages(struct mm_struct *mm) static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { /* Adding mm to ksm is best effort on fork. */ - if (mm_flags_test(MMF_VM_MERGEABLE, oldmm)) + if (mm_flags_test(MMF_VM_MERGEABLE, oldmm)) { + long nr_ksm_zero_pages = atomic_long_read(&mm->ksm_zero_pages); + + mm->ksm_merging_pages = 0; + mm->ksm_rmap_items = 0; + atomic_long_add(nr_ksm_zero_pages, &ksm_zero_pages); __ksm_enter(mm); + } } static inline int ksm_execve(struct mm_struct *mm)

3 weeks, 1 day

2
1
0 0

[PATCH v2 0/2] media: az6007: overall refactor to fix bugs

by Jeongjun Park

This patch series refactors the az6007 driver to address root causes of persistent bugs that have persisted for some time. Jeongjun Park (2): media: az6007: fix out-of-bounds in az6007_i2c_xfer() media: az6007: refactor to properly use dvb-usb-v2 drivers/media/usb/dvb-usb-v2/az6007.c | 211 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------------------------------------------------------------------------------------- 1 file changed, 107 insertions(+), 104 deletions(-)

3 weeks, 1 day

3
5
0 0

FAILED: patch "[PATCH] mm/ksm: fix incorrect KSM counter handling in mm_struct" failed to apply to 6.17-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y git checkout FETCH_HEAD git cherry-pick -x 4d6fc29f36341d7795db1d1819b4c15fe9be7b23 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101357-monorail-juror-352b@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4d6fc29f36341d7795db1d1819b4c15fe9be7b23 Mon Sep 17 00:00:00 2001 From: Donet Tom <donettom(a)linux.ibm.com> Date: Wed, 24 Sep 2025 00:16:59 +0530 Subject: [PATCH] mm/ksm: fix incorrect KSM counter handling in mm_struct during fork Patch series "mm/ksm: Fix incorrect accounting of KSM counters during fork", v3. The first patch in this series fixes the incorrect accounting of KSM counters such as ksm_merging_pages, ksm_rmap_items, and the global ksm_zero_pages during fork. The following patch add a selftest to verify the ksm_merging_pages counter was updated correctly during fork. Test Results ============ Without the first patch ----------------------- # [RUN] test_fork_ksm_merging_page_count not ok 10 ksm_merging_page in child: 32 With the first patch -------------------- # [RUN] test_fork_ksm_merging_page_count ok 10 ksm_merging_pages is not inherited after fork This patch (of 2): Currently, the KSM-related counters in `mm_struct`, such as `ksm_merging_pages`, `ksm_rmap_items`, and `ksm_zero_pages`, are inherited by the child process during fork. This results in inconsistent accounting. When a process uses KSM, identical pages are merged and an rmap item is created for each merged page. The `ksm_merging_pages` and `ksm_rmap_items` counters are updated accordingly. However, after a fork, these counters are copied to the child while the corresponding rmap items are not. As a result, when the child later triggers an unmerge, there are no rmap items present in the child, so the counters remain stale, leading to incorrect accounting. A similar issue exists with `ksm_zero_pages`, which maintains both a global counter and a per-process counter. During fork, the per-process counter is inherited by the child, but the global counter is not incremented. Since the child also references zero pages, the global counter should be updated as well. Otherwise, during zero-page unmerge, both the global and per-process counters are decremented, causing the global counter to become inconsistent. To fix this, ksm_merging_pages and ksm_rmap_items are reset to 0 during fork, and the global ksm_zero_pages counter is updated with the per-process ksm_zero_pages value inherited by the child. This ensures that KSM statistics remain accurate and reflect the activity of each process correctly. Link: https://lkml.kernel.org/r/cover.1758648700.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/7b9870eb67ccc0d79593940d9dbd4a0b39b5d396.17586487… Fixes: 7609385337a4 ("ksm: count ksm merging pages for each process") Fixes: cb4df4cae4f2 ("ksm: count allocated ksm rmap_items for each process") Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Signed-off-by: Donet Tom <donettom(a)linux.ibm.com> Reviewed-by: Chengming Zhou <chengming.zhou(a)linux.dev> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Aboorva Devarajan <aboorvad(a)linux.ibm.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Donet Tom <donettom(a)linux.ibm.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list(a)gmail.com> Cc: Wei Yang <richard.weiyang(a)gmail.com> Cc: xu xin <xu.xin16(a)zte.com.cn> Cc: <stable(a)vger.kernel.org> [6.6+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 22e67ca7cba3..067538fc4d58 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -56,8 +56,14 @@ static inline long mm_ksm_zero_pages(struct mm_struct *mm) static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { /* Adding mm to ksm is best effort on fork. */ - if (mm_flags_test(MMF_VM_MERGEABLE, oldmm)) + if (mm_flags_test(MMF_VM_MERGEABLE, oldmm)) { + long nr_ksm_zero_pages = atomic_long_read(&mm->ksm_zero_pages); + + mm->ksm_merging_pages = 0; + mm->ksm_rmap_items = 0; + atomic_long_add(nr_ksm_zero_pages, &ksm_zero_pages); __ksm_enter(mm); + } } static inline int ksm_execve(struct mm_struct *mm)

3 weeks, 1 day

2
1
0 0

FAILED: patch "[PATCH] tracing: Fix race condition in kprobe initialization causing" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 9cf9aa7b0acfde7545c1a1d912576e9bab28dc6f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101325-slinging-idealism-2cdf@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9cf9aa7b0acfde7545c1a1d912576e9bab28dc6f Mon Sep 17 00:00:00 2001 From: Yuan Chen <chenyuan(a)kylinos.cn> Date: Wed, 1 Oct 2025 03:20:25 +0100 Subject: [PATCH] tracing: Fix race condition in kprobe initialization causing NULL pointer dereference MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There is a critical race condition in kprobe initialization that can lead to NULL pointer dereference and kernel crash. [1135630.084782] Unable to handle kernel paging request at virtual address 0000710a04630000 ... [1135630.260314] pstate: 404003c9 (nZcv DAIF +PAN -UAO) [1135630.269239] pc : kprobe_perf_func+0x30/0x260 [1135630.277643] lr : kprobe_dispatcher+0x44/0x60 [1135630.286041] sp : ffffaeff4977fa40 [1135630.293441] x29: ffffaeff4977fa40 x28: ffffaf015340e400 [1135630.302837] x27: 0000000000000000 x26: 0000000000000000 [1135630.312257] x25: ffffaf029ed108a8 x24: ffffaf015340e528 [1135630.321705] x23: ffffaeff4977fc50 x22: ffffaeff4977fc50 [1135630.331154] x21: 0000000000000000 x20: ffffaeff4977fc50 [1135630.340586] x19: ffffaf015340e400 x18: 0000000000000000 [1135630.349985] x17: 0000000000000000 x16: 0000000000000000 [1135630.359285] x15: 0000000000000000 x14: 0000000000000000 [1135630.368445] x13: 0000000000000000 x12: 0000000000000000 [1135630.377473] x11: 0000000000000000 x10: 0000000000000000 [1135630.386411] x9 : 0000000000000000 x8 : 0000000000000000 [1135630.395252] x7 : 0000000000000000 x6 : 0000000000000000 [1135630.403963] x5 : 0000000000000000 x4 : 0000000000000000 [1135630.412545] x3 : 0000710a04630000 x2 : 0000000000000006 [1135630.421021] x1 : ffffaeff4977fc50 x0 : 0000710a04630000 [1135630.429410] Call trace: [1135630.434828] kprobe_perf_func+0x30/0x260 [1135630.441661] kprobe_dispatcher+0x44/0x60 [1135630.448396] aggr_pre_handler+0x70/0xc8 [1135630.454959] kprobe_breakpoint_handler+0x140/0x1e0 [1135630.462435] brk_handler+0xbc/0xd8 [1135630.468437] do_debug_exception+0x84/0x138 [1135630.475074] el1_dbg+0x18/0x8c [1135630.480582] security_file_permission+0x0/0xd0 [1135630.487426] vfs_write+0x70/0x1c0 [1135630.493059] ksys_write+0x5c/0xc8 [1135630.498638] __arm64_sys_write+0x24/0x30 [1135630.504821] el0_svc_common+0x78/0x130 [1135630.510838] el0_svc_handler+0x38/0x78 [1135630.516834] el0_svc+0x8/0x1b0 kernel/trace/trace_kprobe.c: 1308 0xffff3df8995039ec <kprobe_perf_func+0x2c>: ldr x21, [x24,#120] include/linux/compiler.h: 294 0xffff3df8995039f0 <kprobe_perf_func+0x30>: ldr x1, [x21,x0] kernel/trace/trace_kprobe.c 1308: head = this_cpu_ptr(call->perf_events); 1309: if (hlist_empty(head)) 1310: return 0; crash> struct trace_event_call -o struct trace_event_call { ... [120] struct hlist_head *perf_events; //(call->perf_event) ... } crash> struct trace_event_call ffffaf015340e528 struct trace_event_call { ... perf_events = 0xffff0ad5fa89f088, //this value is correct, but x21 = 0 ... } Race Condition Analysis: The race occurs between kprobe activation and perf_events initialization: CPU0 CPU1 ==== ==== perf_kprobe_init perf_trace_event_init tp_event->perf_events = list;(1) tp_event->class->reg (2)← KPROBE ACTIVE Debug exception triggers ... kprobe_dispatcher kprobe_perf_func (tk->tp.flags & TP_FLAG_PROFILE) head = this_cpu_ptr(call->perf_events)(3) (perf_events is still NULL) Problem: 1. CPU0 executes (1) assigning tp_event->perf_events = list 2. CPU0 executes (2) enabling kprobe functionality via class->reg() 3. CPU1 triggers and reaches kprobe_dispatcher 4. CPU1 checks TP_FLAG_PROFILE - condition passes (step 2 completed) 5. CPU1 calls kprobe_perf_func() and crashes at (3) because call->perf_events is still NULL CPU1 sees that kprobe functionality is enabled but does not see that perf_events has been assigned. Add pairing read and write memory barriers to guarantee that if CPU1 sees that kprobe functionality is enabled, it must also see that perf_events has been assigned. Link: https://lore.kernel.org/all/20251001022025.44626-1-chenyuan_fl@163.com/ Fixes: 50d780560785 ("tracing/kprobes: Add probe handler dispatcher to support perf and ftrace concurrent use") Cc: stable(a)vger.kernel.org Signed-off-by: Yuan Chen <chenyuan(a)kylinos.cn> Signed-off-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index b36ade43d4b3..ad9d6347b5fa 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -522,13 +522,14 @@ static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip, void *entry_data) { struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp); + unsigned int flags = trace_probe_load_flag(&tf->tp); int ret = 0; - if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE)) + if (flags & TP_FLAG_TRACE) fentry_trace_func(tf, entry_ip, fregs); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) ret = fentry_perf_func(tf, entry_ip, fregs); #endif return ret; @@ -540,11 +541,12 @@ static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip, void *entry_data) { struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp); + unsigned int flags = trace_probe_load_flag(&tf->tp); - if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE)) + if (flags & TP_FLAG_TRACE) fexit_trace_func(tf, entry_ip, ret_ip, fregs, entry_data); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) fexit_perf_func(tf, entry_ip, ret_ip, fregs, entry_data); #endif } diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index fa60362a3f31..ee8171b19bee 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1815,14 +1815,15 @@ static int kprobe_register(struct trace_event_call *event, static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) { struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); + unsigned int flags = trace_probe_load_flag(&tk->tp); int ret = 0; raw_cpu_inc(*tk->nhit); - if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) + if (flags & TP_FLAG_TRACE) kprobe_trace_func(tk, regs); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) ret = kprobe_perf_func(tk, regs); #endif return ret; @@ -1834,6 +1835,7 @@ kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) { struct kretprobe *rp = get_kretprobe(ri); struct trace_kprobe *tk; + unsigned int flags; /* * There is a small chance that get_kretprobe(ri) returns NULL when @@ -1846,10 +1848,11 @@ kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) tk = container_of(rp, struct trace_kprobe, rp); raw_cpu_inc(*tk->nhit); - if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) + flags = trace_probe_load_flag(&tk->tp); + if (flags & TP_FLAG_TRACE) kretprobe_trace_func(tk, ri, regs); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) kretprobe_perf_func(tk, ri, regs); #endif return 0; /* We don't tweak kernel, so just return 0 */ diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 842383fbc03b..08b5bda24da2 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -271,16 +271,21 @@ struct event_file_link { struct list_head list; }; +static inline unsigned int trace_probe_load_flag(struct trace_probe *tp) +{ + return smp_load_acquire(&tp->event->flags); +} + static inline bool trace_probe_test_flag(struct trace_probe *tp, unsigned int flag) { - return !!(tp->event->flags & flag); + return !!(trace_probe_load_flag(tp) & flag); } static inline void trace_probe_set_flag(struct trace_probe *tp, unsigned int flag) { - tp->event->flags |= flag; + smp_store_release(&tp->event->flags, tp->event->flags | flag); } static inline void trace_probe_clear_flag(struct trace_probe *tp, diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 8b0bcc0d8f41..430d09c49462 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1547,6 +1547,7 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs, struct trace_uprobe *tu; struct uprobe_dispatch_data udd; struct uprobe_cpu_buffer *ucb = NULL; + unsigned int flags; int ret = 0; tu = container_of(con, struct trace_uprobe, consumer); @@ -1561,11 +1562,12 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs, if (WARN_ON_ONCE(!uprobe_cpu_buffer)) return 0; - if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) + flags = trace_probe_load_flag(&tu->tp); + if (flags & TP_FLAG_TRACE) ret |= uprobe_trace_func(tu, regs, &ucb); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) ret |= uprobe_perf_func(tu, regs, &ucb); #endif uprobe_buffer_put(ucb); @@ -1579,6 +1581,7 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con, struct trace_uprobe *tu; struct uprobe_dispatch_data udd; struct uprobe_cpu_buffer *ucb = NULL; + unsigned int flags; tu = container_of(con, struct trace_uprobe, consumer); @@ -1590,11 +1593,12 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con, if (WARN_ON_ONCE(!uprobe_cpu_buffer)) return 0; - if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE)) + flags = trace_probe_load_flag(&tu->tp); + if (flags & TP_FLAG_TRACE) uretprobe_trace_func(tu, func, regs, &ucb); #ifdef CONFIG_PERF_EVENTS - if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE)) + if (flags & TP_FLAG_PROFILE) uretprobe_perf_func(tu, func, regs, &ucb); #endif uprobe_buffer_put(ucb);

3 weeks, 1 day

2
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0 0

FAILED: patch "[PATCH] dm: fix NULL pointer dereference in __dm_suspend()" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 8d33a030c566e1f105cd5bf27f37940b6367f3be # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101316-handmade-imaginary-edf0@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8d33a030c566e1f105cd5bf27f37940b6367f3be Mon Sep 17 00:00:00 2001 From: Zheng Qixing <zhengqixing(a)huawei.com> Date: Tue, 26 Aug 2025 15:42:04 +0800 Subject: [PATCH] dm: fix NULL pointer dereference in __dm_suspend() There is a race condition between dm device suspend and table load that can lead to null pointer dereference. The issue occurs when suspend is invoked before table load completes: BUG: kernel NULL pointer dereference, address: 0000000000000054 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50 Call Trace: <TASK> blk_mq_quiesce_queue+0x2c/0x50 dm_stop_queue+0xd/0x20 __dm_suspend+0x130/0x330 dm_suspend+0x11a/0x180 dev_suspend+0x27e/0x560 ctl_ioctl+0x4cf/0x850 dm_ctl_ioctl+0xd/0x20 vfs_ioctl+0x1d/0x50 __se_sys_ioctl+0x9b/0xc0 __x64_sys_ioctl+0x19/0x30 x64_sys_call+0x2c4a/0x4620 do_syscall_64+0x9e/0x1b0 The issue can be triggered as below: T1 T2 dm_suspend table_load __dm_suspend dm_setup_md_queue dm_mq_init_request_queue blk_mq_init_allocated_queue => q->mq_ops = set->ops; (1) dm_stop_queue / dm_wait_for_completion => q->tag_set NULL pointer! (2) => q->tag_set = set; (3) Fix this by checking if a valid table (map) exists before performing request-based suspend and waiting for target I/O. When map is NULL, skip these table-dependent suspend steps. Even when map is NULL, no I/O can reach any target because there is no table loaded; I/O submitted in this state will fail early in the DM layer. Skipping the table-dependent suspend logic in this case is safe and avoids NULL pointer dereferences. Fixes: c4576aed8d85 ("dm: fix request-based dm's use of dm_wait_for_completion") Cc: stable(a)vger.kernel.org Signed-off-by: Zheng Qixing <zhengqixing(a)huawei.com> Signed-off-by: Mikulas Patocka <mpatocka(a)redhat.com> diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 7222f20c1a83..66dd5f6ce778 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2908,7 +2908,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, { bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; - int r; + int r = 0; lockdep_assert_held(&md->suspend_lock); @@ -2960,7 +2960,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, * Stop md->queue before flushing md->wq in case request-based * dm defers requests to md->wq from md->queue. */ - if (dm_request_based(md)) { + if (map && dm_request_based(md)) { dm_stop_queue(md->queue); set_bit(DMF_QUEUE_STOPPED, &md->flags); } @@ -2972,7 +2972,8 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, * We call dm_wait_for_completion to wait for all existing requests * to finish. */ - r = dm_wait_for_completion(md, task_state); + if (map) + r = dm_wait_for_completion(md, task_state); if (!r) set_bit(dmf_suspended_flag, &md->flags);

3 weeks, 1 day

2
1
0 0

ORDER 8745631

by Mrs. Diana Owen

Greetings, I hope this email finds you well. I am Mrs. Diana Owen contacting you from Reality Trading Group Ltd India. . As a new growing company, we are looking for reliable company of your product as seen in your website for urgent purchase order basis. Could you please give me more details and specification of your products. We also need your products catalog, MOQ, Production Lead Time and Unit price? Best Regards, Mrs. Diana Owen Purchase Manager Company: Reality Trading Group Ltd

3 weeks, 1 day

1
0
0 0

[PATCH RESEND v3 0/3] phy: qcom: edp: Add missing ref clock to x1e80100

by Abel Vesa

According to documentation, the DP PHY on x1e80100 has another clock called ref. The current X Elite devices supported upstream work fine without this clock, because the boot firmware leaves this clock enabled. But we should not rely on that. Also, when it comes to power management, this clock needs to be also disabled on suspend. So even though this change breaks the ABI, it is needed in order to make we disable this clock on runtime PM, when that is going to be enabled in the driver. So rework the driver to allow different number of clocks, fix the dt-bindings schema and add the clock to the DT node as well. Signed-off-by: Abel Vesa <abel.vesa(a)linaro.org> --- Changes in v3 (resend) - picked-up Krzysztof's R-b tag for bindings patch Changes in v3: - Use dev_err_probe() on clocks parsing failure. - Explain why the ABI break is necessary. - Drop the extra 'clk' suffix from the clock name. So ref instead of refclk. - Link to v2: https://lore.kernel.org/r/20250903-phy-qcom-edp-add-missing-refclk-v2-0-d88… Changes in v2: - Fix schema by adding the minItems, as suggested by Krzysztof. - Use devm_clk_bulk_get_all, as suggested by Konrad. - Rephrase the commit messages to reflect the flexible number of clocks. - Link to v1: https://lore.kernel.org/r/20250730-phy-qcom-edp-add-missing-refclk-v1-0-6f7… --- Abel Vesa (3): dt-bindings: phy: qcom-edp: Add missing clock for X Elite phy: qcom: edp: Make the number of clocks flexible arm64: dts: qcom: Add missing TCSR ref clock to the DP PHYs .../devicetree/bindings/phy/qcom,edp-phy.yaml | 28 +++++++++++++++++++++- arch/arm64/boot/dts/qcom/x1e80100.dtsi | 12 ++++++---- drivers/phy/qualcomm/phy-qcom-edp.c | 16 ++++++------- 3 files changed, 43 insertions(+), 13 deletions(-) --- base-commit: 52ba76324a9d7c39830c850999210a36ef023cde change-id: 20250730-phy-qcom-edp-add-missing-refclk-5ab82828f8e7 Best regards, -- Abel Vesa <abel.vesa(a)linaro.org>

3 weeks, 1 day

2
5
0 0

[PATCH v2 1/1] hung_task: fix warnings caused by unaligned lock pointers

by Lance Yang

From: Lance Yang <lance.yang(a)linux.dev> The blocker tracking mechanism assumes that lock pointers are at least 4-byte aligned to use their lower bits for type encoding. However, as reported by Eero Tamminen, some architectures like m68k only guarantee 2-byte alignment of 32-bit values. This breaks the assumption and causes two related WARN_ON_ONCE checks to trigger. To fix this, the runtime checks are adjusted to silently ignore any lock that is not 4-byte aligned, effectively disabling the feature in such cases and avoiding the related warnings. Thanks to Geert Uytterhoeven for bisecting! Reported-by: Eero Tamminen <oak(a)helsinkinet.fi> Closes: https://lore.kernel.org/lkml/CAMuHMdW7Ab13DdGs2acMQcix5ObJK0O2dG_Fxzr8_g58R… Fixes: e711faaafbe5 ("hung_task: replace blocker_mutex with encoded blocker") Cc: <stable(a)vger.kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Signed-off-by: Lance Yang <lance.yang(a)linux.dev> --- v1 -> v2: - Pick RB from Masami - thanks! - Update the changelog and comments - https://lore.kernel.org/lkml/20250823050036.7748-1-lance.yang@linux.dev/ include/linux/hung_task.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/hung_task.h b/include/linux/hung_task.h index 34e615c76ca5..c4403eeb7144 100644 --- a/include/linux/hung_task.h +++ b/include/linux/hung_task.h @@ -20,6 +20,10 @@ * always zero. So we can use these bits to encode the specific blocking * type. * + * Note that on architectures where this is not guaranteed, or for any + * unaligned lock, this tracking mechanism is silently skipped for that + * lock. + * * Type encoding: * 00 - Blocked on mutex (BLOCKER_TYPE_MUTEX) * 01 - Blocked on semaphore (BLOCKER_TYPE_SEM) @@ -45,7 +49,7 @@ static inline void hung_task_set_blocker(void *lock, unsigned long type) * If the lock pointer matches the BLOCKER_TYPE_MASK, return * without writing anything. */ - if (WARN_ON_ONCE(lock_ptr & BLOCKER_TYPE_MASK)) + if (lock_ptr & BLOCKER_TYPE_MASK) return; WRITE_ONCE(current->blocker, lock_ptr | type); @@ -53,8 +57,6 @@ static inline void hung_task_set_blocker(void *lock, unsigned long type) static inline void hung_task_clear_blocker(void) { - WARN_ON_ONCE(!READ_ONCE(current->blocker)); - WRITE_ONCE(current->blocker, 0UL); } -- 2.49.0

3 weeks, 1 day

9
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