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FAILED: patch "[PATCH] net: netpoll: fix incorrect refcount handling causing" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112007-gyration-fifty-ac52@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 Mon Sep 17 00:00:00 2001 From: Breno Leitao <leitao(a)debian.org> Date: Fri, 7 Nov 2025 06:03:37 -0800 Subject: [PATCH] net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18 ("netpoll: fix use after free") incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks. Scenario causing lack of proper cleanup: 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one. 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1. - Now dev->npinfo->refcnt = 2; - There is just one npinfo associated to the netdev. 3) When the first netpolls goes to clean up: - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt. - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);` - Set dev->npinfo = NULL, without proper cleanup - No ->ndo_netpoll_cleanup() is either called 4) Now the second target tries to clean up - The second cleanup fails because np->dev->npinfo is already NULL. * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance) - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak. Revert commit efa95b01da18 ("netpoll: fix use after free") and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior. Cc: <stable(a)vger.kernel.org> # 3.17.x Cc: Jay Vosburgh <jv(a)jvosburgh.net> Fixes: efa95b01da18 ("netpoll: fix use after free") Signed-off-by: Breno Leitao <leitao(a)debian.org> Reviewed-by: Simon Horman <horms(a)kernel.org> Link: https://patch.msgid.link/20251107-netconsole_torture-v10-1-749227b55f63@deb… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/net/core/netpoll.c b/net/core/netpoll.c index c85f740065fc..331764845e8f 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -811,6 +811,10 @@ static void __netpoll_cleanup(struct netpoll *np) if (!npinfo) return; + /* At this point, there is a single npinfo instance per netdevice, and + * its refcnt tracks how many netpoll structures are linked to it. We + * only perform npinfo cleanup when the refcnt decrements to zero. + */ if (refcount_dec_and_test(&npinfo->refcnt)) { const struct net_device_ops *ops; @@ -820,8 +824,7 @@ static void __netpoll_cleanup(struct netpoll *np) RCU_INIT_POINTER(np->dev->npinfo, NULL); call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); - } else - RCU_INIT_POINTER(np->dev->npinfo, NULL); + } skb_pool_flush(np); }

1 day, 5 hours

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[PATCH 1/2] drm/xe: Silence allocation warnings for sync arrays

by Shuicheng Lin

args->num_syncs comes from userspace and may be large or fuzzed. When kcalloc() attempts a large allocation, the allocator may emit warning like below, even though the driver already returns -ENOMEM safely. Suppress it by using __GFP_NOWARN when allocating the sync array. " WARNING: CPU: 0 PID: 1217 at mm/page_alloc.c:5124 __alloc_frozen_pages_noprof+0x2f8/0x2180 mm/page_alloc.c:5124 ... Call Trace: <TASK> alloc_pages_mpol+0xe4/0x330 mm/mempolicy.c:2416 ___kmalloc_large_node+0xd8/0x110 mm/slub.c:4317 __kmalloc_large_node_noprof+0x18/0xe0 mm/slub.c:4348 __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_noprof+0x3d4/0x4b0 mm/slub.c:4388 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] xe_exec_ioctl+0xa47/0x1e70 drivers/gpu/drm/xe/xe_exec.c:158 drm_ioctl_kernel+0x1f1/0x3e0 drivers/gpu/drm/drm_ioctl.c:797 drm_ioctl+0x5e7/0xc50 drivers/gpu/drm/drm_ioctl.c:894 xe_drm_ioctl+0x10b/0x170 drivers/gpu/drm/xe/xe_device.c:224 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl fs/ioctl.c:584 [inline] __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xbb/0x380 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... " Reported-by: Koen Koning <koen.koning(a)intel.com> Reported-by: Peter Senna Tschudin <peter.senna(a)linux.intel.com> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6450 Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Cc: <stable(a)vger.kernel.org> # v6.12+ Cc: Matthew Brost <matthew.brost(a)intel.com> Signed-off-by: Shuicheng Lin <shuicheng.lin(a)intel.com> --- drivers/gpu/drm/xe/xe_exec.c | 3 ++- drivers/gpu/drm/xe/xe_vm.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c index 4d81210e41f5..7ef78a94e168 100644 --- a/drivers/gpu/drm/xe/xe_exec.c +++ b/drivers/gpu/drm/xe/xe_exec.c @@ -162,7 +162,8 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file) } if (args->num_syncs) { - syncs = kcalloc(args->num_syncs, sizeof(*syncs), GFP_KERNEL); + syncs = kcalloc(args->num_syncs, sizeof(*syncs), + GFP_KERNEL | __GFP_NOWARN); if (!syncs) { err = -ENOMEM; goto err_exec_queue; diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index f9989a7a710c..8cebf7285640 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -3640,7 +3640,8 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file) } if (args->num_syncs) { - syncs = kcalloc(args->num_syncs, sizeof(*syncs), GFP_KERNEL); + syncs = kcalloc(args->num_syncs, sizeof(*syncs), + GFP_KERNEL | __GFP_NOWARN); if (!syncs) { err = -ENOMEM; goto put_obj; -- 2.49.0

1 day, 7 hours

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[for-next][PATCH 04/16] rtla/timerlat_bpf: Stop tracing on user latency

by Steven Rostedt

From: Tomas Glozar <tglozar(a)redhat.com> rtla-timerlat allows a *thread* latency threshold to be set via the -T/--thread option. However, the timerlat tracer calls this *total* latency (stop_tracing_total_us), and stops tracing also when the return-to-user latency is over the threshold. Change the behavior of the timerlat BPF program to reflect what the timerlat tracer is doing, to avoid discrepancy between stopping collecting data in the BPF program and stopping tracing in the timerlat tracer. Cc: stable(a)vger.kernel.org Fixes: e34293ddcebd ("rtla/timerlat: Add BPF skeleton to collect samples") Reviewed-by: Wander Lairson Costa <wander(a)redhat.com> Link: https://lore.kernel.org/r/20251006143100.137255-1-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar(a)redhat.com> --- tools/tracing/rtla/src/timerlat.bpf.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/tracing/rtla/src/timerlat.bpf.c b/tools/tracing/rtla/src/timerlat.bpf.c index 084cd10c21fc..e2265b5d6491 100644 --- a/tools/tracing/rtla/src/timerlat.bpf.c +++ b/tools/tracing/rtla/src/timerlat.bpf.c @@ -148,6 +148,9 @@ int handle_timerlat_sample(struct trace_event_raw_timerlat_sample *tp_args) } else { update_main_hist(&hist_user, bucket); update_summary(&summary_user, latency, bucket); + + if (thread_threshold != 0 && latency_us >= thread_threshold) + set_stop_tracing(); } return 0; -- 2.51.0

1 day, 7 hours

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FAILED: patch "[PATCH] KVM: SVM: Mark VMCB_LBR dirty when MSR_IA32_DEBUGCTLMSR is" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-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-6.1.y git checkout FETCH_HEAD git cherry-pick -x dc55b3c3f61246e483e50c85d8d5366f9567e188 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112036-abdominal-envelope-7ca0@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From dc55b3c3f61246e483e50c85d8d5366f9567e188 Mon Sep 17 00:00:00 2001 From: Yosry Ahmed <yosry.ahmed(a)linux.dev> Date: Sat, 8 Nov 2025 00:45:19 +0000 Subject: [PATCH] KVM: SVM: Mark VMCB_LBR dirty when MSR_IA32_DEBUGCTLMSR is updated The APM lists the DbgCtlMsr field as being tracked by the VMCB_LBR clean bit. Always clear the bit when MSR_IA32_DEBUGCTLMSR is updated. The history is complicated, it was correctly cleared for L1 before commit 1d5a1b5860ed ("KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running"). At that point svm_set_msr() started to rely on svm_update_lbrv() to clear the bit, but when nested virtualization is enabled the latter does not always clear it even if MSR_IA32_DEBUGCTLMSR changed. Go back to clearing it directly in svm_set_msr(). Fixes: 1d5a1b5860ed ("KVM: x86: nSVM: correctly virtualize LBR msrs when L2 is running") Reported-by: Matteo Rizzo <matteorizzo(a)google.com> Reported-by: evn(a)google.com Co-developed-by: Jim Mattson <jmattson(a)google.com> Signed-off-by: Jim Mattson <jmattson(a)google.com> Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> Link: https://patch.msgid.link/20251108004524.1600006-2-yosry.ahmed@linux.dev Cc: stable(a)vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 76055c0ba177..39538098002b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3004,7 +3004,11 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) if (data & DEBUGCTL_RESERVED_BITS) return 1; + if (svm_get_lbr_vmcb(svm)->save.dbgctl == data) + break; + svm_get_lbr_vmcb(svm)->save.dbgctl = data; + vmcb_mark_dirty(svm->vmcb, VMCB_LBR); svm_update_lbrv(vcpu); break; case MSR_VM_HSAVE_PA:

1 day, 8 hours

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[PATCH v1 0/2] mm: skip wait in wait_sb_inodes() for hangable-writeback mappings

by Joanne Koong

As reported by Athul upstream in [1], there is a userspace regression caused by commit 0c58a97f919c ("fuse: remove tmp folio for writebacks and internal rb tree") where if there is a bug in a fuse server that causes the server to never complete writeback, it will make wait_sb_inodes() wait forever, causing sync paths to hang. This is a resubmission of this patch [2] that was dropped from the original series due to a buggy/malicious server still being able to hold up sync() / the system in other ways if they wanted to, but the wait_sb_inodes() path is particularly common and easier to hit for malfunctioning servers. Thanks, Joanne [1] https://lore.kernel.org/regressions/CAJnrk1ZjQ8W8NzojsvJPRXiv9TuYPNdj8Ye7=C… [2] https://lore.kernel.org/linux-fsdevel/20241122232359.429647-4-joannelkoong@… Joanne Koong (2): mm: rename AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM to AS_WRITEBACK_MAY_HANG fs/writeback: skip inodes with potential writeback hang in wait_sb_inodes() fs/fs-writeback.c | 3 +++ fs/fuse/file.c | 2 +- include/linux/pagemap.h | 10 +++++----- mm/vmscan.c | 3 +-- 4 files changed, 10 insertions(+), 8 deletions(-) -- 2.47.3

1 day, 9 hours

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Re,

by Ms Jacq.

Please view the attached Microsoft word to read your email. Regards Ms Jacq.

1 day, 9 hours

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FAILED: patch "[PATCH] fs/proc: fix uaf in proc_readdir_de()" 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 895b4c0c79b092d732544011c3cecaf7322c36a1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112019-mantra-unwind-1db7@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 895b4c0c79b092d732544011c3cecaf7322c36a1 Mon Sep 17 00:00:00 2001 From: Wei Yang <albinwyang(a)tencent.com> Date: Sat, 25 Oct 2025 10:42:33 +0800 Subject: [PATCH] fs/proc: fix uaf in proc_readdir_de() Pde is erased from subdir rbtree through rb_erase(), but not set the node to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE() set the erased node to EMPTY, then pde_subdir_next() will return NULL to avoid uaf access. We found an uaf issue while using stress-ng testing, need to run testcase getdent and tun in the same time. The steps of the issue is as follows: 1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current pde is tun3; 2) in the [time windows] unregister netdevice tun3 and tun2, and erase them from rbtree. erase tun3 first, and then erase tun2. the pde(tun2) will be released to slab; 3) continue to getdent process, then pde_subdir_next() will return pde(tun2) which is released, it will case uaf access. CPU 0 | CPU 1 ------------------------------------------------------------------------- traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2 sys_getdents64() | iterate_dir() | proc_readdir() | proc_readdir_de() | snmp6_unregister_dev() pde_get(de); | proc_remove() read_unlock(&proc_subdir_lock); | remove_proc_subtree() | write_lock(&proc_subdir_lock); [time window] | rb_erase(&root->subdir_node, &parent->subdir); | write_unlock(&proc_subdir_lock); read_lock(&proc_subdir_lock); | next = pde_subdir_next(de); | pde_put(de); | de = next; //UAF | rbtree of dev_snmp6 | pde(tun3) / \ NULL pde(tun2) Link: https://lkml.kernel.org/r/20251025024233.158363-1-albin_yang@163.com Signed-off-by: Wei Yang <albinwyang(a)tencent.com> Cc: Al Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Cc: wangzijie <wangzijie1(a)honor.com> Cc: Alexey Dobriyan <adobriyan(a)gmail.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 176281112273..501889856461 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -698,6 +698,12 @@ void pde_put(struct proc_dir_entry *pde) } } +static void pde_erase(struct proc_dir_entry *pde, struct proc_dir_entry *parent) +{ + rb_erase(&pde->subdir_node, &parent->subdir); + RB_CLEAR_NODE(&pde->subdir_node); +} + /* * Remove a /proc entry and free it if it's not currently in use. */ @@ -720,7 +726,7 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) WARN(1, "removing permanent /proc entry '%s'", de->name); de = NULL; } else { - rb_erase(&de->subdir_node, &parent->subdir); + pde_erase(de, parent); if (S_ISDIR(de->mode)) parent->nlink--; } @@ -764,7 +770,7 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) root->parent->name, root->name); return -EINVAL; } - rb_erase(&root->subdir_node, &parent->subdir); + pde_erase(root, parent); de = root; while (1) { @@ -776,7 +782,7 @@ int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) next->parent->name, next->name); return -EINVAL; } - rb_erase(&next->subdir_node, &de->subdir); + pde_erase(next, de); de = next; continue; }

1 day, 10 hours

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FAILED: patch "[PATCH] net: netpoll: fix incorrect refcount handling causing" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112006-author-harmony-d5f7@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 Mon Sep 17 00:00:00 2001 From: Breno Leitao <leitao(a)debian.org> Date: Fri, 7 Nov 2025 06:03:37 -0800 Subject: [PATCH] net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18 ("netpoll: fix use after free") incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks. Scenario causing lack of proper cleanup: 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one. 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1. - Now dev->npinfo->refcnt = 2; - There is just one npinfo associated to the netdev. 3) When the first netpolls goes to clean up: - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt. - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);` - Set dev->npinfo = NULL, without proper cleanup - No ->ndo_netpoll_cleanup() is either called 4) Now the second target tries to clean up - The second cleanup fails because np->dev->npinfo is already NULL. * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance) - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak. Revert commit efa95b01da18 ("netpoll: fix use after free") and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior. Cc: <stable(a)vger.kernel.org> # 3.17.x Cc: Jay Vosburgh <jv(a)jvosburgh.net> Fixes: efa95b01da18 ("netpoll: fix use after free") Signed-off-by: Breno Leitao <leitao(a)debian.org> Reviewed-by: Simon Horman <horms(a)kernel.org> Link: https://patch.msgid.link/20251107-netconsole_torture-v10-1-749227b55f63@deb… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/net/core/netpoll.c b/net/core/netpoll.c index c85f740065fc..331764845e8f 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -811,6 +811,10 @@ static void __netpoll_cleanup(struct netpoll *np) if (!npinfo) return; + /* At this point, there is a single npinfo instance per netdevice, and + * its refcnt tracks how many netpoll structures are linked to it. We + * only perform npinfo cleanup when the refcnt decrements to zero. + */ if (refcount_dec_and_test(&npinfo->refcnt)) { const struct net_device_ops *ops; @@ -820,8 +824,7 @@ static void __netpoll_cleanup(struct netpoll *np) RCU_INIT_POINTER(np->dev->npinfo, NULL); call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); - } else - RCU_INIT_POINTER(np->dev->npinfo, NULL); + } skb_pool_flush(np); }

1 day, 11 hours

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FAILED: patch "[PATCH] mm/huge_memory: preserve PG_has_hwpoisoned if a folio is" 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 fa5a061700364bc28ee1cb1095372f8033645dcb # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112056-isolating-punisher-7be9@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From fa5a061700364bc28ee1cb1095372f8033645dcb Mon Sep 17 00:00:00 2001 From: Zi Yan <ziy(a)nvidia.com> Date: Wed, 22 Oct 2025 23:05:21 -0400 Subject: [PATCH] mm/huge_memory: preserve PG_has_hwpoisoned if a folio is split to >0 order folio split clears PG_has_hwpoisoned, but the flag should be preserved in after-split folios containing pages with PG_hwpoisoned flag if the folio is split to >0 order folios. Scan all pages in a to-be-split folio to determine which after-split folios need the flag. An alternatives is to change PG_has_hwpoisoned to PG_maybe_hwpoisoned to avoid the scan and set it on all after-split folios, but resulting false positive has undesirable negative impact. To remove false positive, caller of folio_test_has_hwpoisoned() and folio_contain_hwpoisoned_page() needs to do the scan. That might be causing a hassle for current and future callers and more costly than doing the scan in the split code. More details are discussed in [1]. This issue can be exposed via: 1. splitting a has_hwpoisoned folio to >0 order from debugfs interface; 2. truncating part of a has_hwpoisoned folio in truncate_inode_partial_folio(). And later accesses to a hwpoisoned page could be possible due to the missing has_hwpoisoned folio flag. This will lead to MCE errors. Link: https://lore.kernel.org/all/CAHbLzkoOZm0PXxE9qwtF4gKR=cpRXrSrJ9V9Pm2DJexs98… [1] Link: https://lkml.kernel.org/r/20251023030521.473097-1-ziy@nvidia.com Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Zi Yan <ziy(a)nvidia.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Yang Shi <yang(a)os.amperecomputing.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Lance Yang <lance.yang(a)linux.dev> Reviewed-by: Miaohe Lin <linmiaohe(a)huawei.com> Reviewed-by: Baolin Wang <baolin.wang(a)linux.alibaba.com> Reviewed-by: Wei Yang <richard.weiyang(a)gmail.com> Cc: Pankaj Raghav <kernel(a)pankajraghav.com> Cc: Barry Song <baohua(a)kernel.org> Cc: Dev Jain <dev.jain(a)arm.com> Cc: Jane Chu <jane.chu(a)oracle.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Luis Chamberalin <mcgrof(a)kernel.org> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Naoya Horiguchi <nao.horiguchi(a)gmail.com> Cc: Nico Pache <npache(a)redhat.com> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/huge_memory.c b/mm/huge_memory.c index feac4aef7dfb..b4ff49d96501 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3263,6 +3263,14 @@ bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins) caller_pins; } +static bool page_range_has_hwpoisoned(struct page *page, long nr_pages) +{ + for (; nr_pages; page++, nr_pages--) + if (PageHWPoison(page)) + return true; + return false; +} + /* * It splits @folio into @new_order folios and copies the @folio metadata to * all the resulting folios. @@ -3270,17 +3278,24 @@ bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins) static void __split_folio_to_order(struct folio *folio, int old_order, int new_order) { + /* Scan poisoned pages when split a poisoned folio to large folios */ + const bool handle_hwpoison = folio_test_has_hwpoisoned(folio) && new_order; long new_nr_pages = 1 << new_order; long nr_pages = 1 << old_order; long i; + folio_clear_has_hwpoisoned(folio); + + /* Check first new_nr_pages since the loop below skips them */ + if (handle_hwpoison && + page_range_has_hwpoisoned(folio_page(folio, 0), new_nr_pages)) + folio_set_has_hwpoisoned(folio); /* * Skip the first new_nr_pages, since the new folio from them have all * the flags from the original folio. */ for (i = new_nr_pages; i < nr_pages; i += new_nr_pages) { struct page *new_head = &folio->page + i; - /* * Careful: new_folio is not a "real" folio before we cleared PageTail. * Don't pass it around before clear_compound_head(). @@ -3322,6 +3337,10 @@ static void __split_folio_to_order(struct folio *folio, int old_order, (1L << PG_dirty) | LRU_GEN_MASK | LRU_REFS_MASK)); + if (handle_hwpoison && + page_range_has_hwpoisoned(new_head, new_nr_pages)) + folio_set_has_hwpoisoned(new_folio); + new_folio->mapping = folio->mapping; new_folio->index = folio->index + i; @@ -3422,8 +3441,6 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, if (folio_test_anon(folio)) mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1); - folio_clear_has_hwpoisoned(folio); - /* * split to new_order one order at a time. For uniform split, * folio is split to new_order directly.

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FAILED: patch "[PATCH] net: netpoll: fix incorrect refcount handling causing" 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 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112005-polio-gratify-8d3b@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 49c8d2c1f94cc2f4d1a108530d7ba52614b874c2 Mon Sep 17 00:00:00 2001 From: Breno Leitao <leitao(a)debian.org> Date: Fri, 7 Nov 2025 06:03:37 -0800 Subject: [PATCH] net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18 ("netpoll: fix use after free") incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks. Scenario causing lack of proper cleanup: 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one. 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1. - Now dev->npinfo->refcnt = 2; - There is just one npinfo associated to the netdev. 3) When the first netpolls goes to clean up: - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt. - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);` - Set dev->npinfo = NULL, without proper cleanup - No ->ndo_netpoll_cleanup() is either called 4) Now the second target tries to clean up - The second cleanup fails because np->dev->npinfo is already NULL. * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance) - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak. Revert commit efa95b01da18 ("netpoll: fix use after free") and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior. Cc: <stable(a)vger.kernel.org> # 3.17.x Cc: Jay Vosburgh <jv(a)jvosburgh.net> Fixes: efa95b01da18 ("netpoll: fix use after free") Signed-off-by: Breno Leitao <leitao(a)debian.org> Reviewed-by: Simon Horman <horms(a)kernel.org> Link: https://patch.msgid.link/20251107-netconsole_torture-v10-1-749227b55f63@deb… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/net/core/netpoll.c b/net/core/netpoll.c index c85f740065fc..331764845e8f 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -811,6 +811,10 @@ static void __netpoll_cleanup(struct netpoll *np) if (!npinfo) return; + /* At this point, there is a single npinfo instance per netdevice, and + * its refcnt tracks how many netpoll structures are linked to it. We + * only perform npinfo cleanup when the refcnt decrements to zero. + */ if (refcount_dec_and_test(&npinfo->refcnt)) { const struct net_device_ops *ops; @@ -820,8 +824,7 @@ static void __netpoll_cleanup(struct netpoll *np) RCU_INIT_POINTER(np->dev->npinfo, NULL); call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); - } else - RCU_INIT_POINTER(np->dev->npinfo, NULL); + } skb_pool_flush(np); }

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