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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 week, 4 days

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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 week, 4 days

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Re,

by Ms Jacq.

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

1 week, 4 days

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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 week, 4 days

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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.

1 week, 4 days

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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); }

1 week, 4 days

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FAILED: patch "[PATCH] mm/huge_memory: do not change split_huge_page*() target order" 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 77008e1b2ef73249bceb078a321a3ff6bc087afb # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112015-revolving-professed-8d2d@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 77008e1b2ef73249bceb078a321a3ff6bc087afb Mon Sep 17 00:00:00 2001 From: Zi Yan <ziy(a)nvidia.com> Date: Thu, 16 Oct 2025 21:36:30 -0400 Subject: [PATCH] mm/huge_memory: do not change split_huge_page*() target order silently Page cache folios from a file system that support large block size (LBS) can have minimal folio order greater than 0, thus a high order folio might not be able to be split down to order-0. Commit e220917fa507 ("mm: split a folio in minimum folio order chunks") bumps the target order of split_huge_page*() to the minimum allowed order when splitting a LBS folio. This causes confusion for some split_huge_page*() callers like memory failure handling code, since they expect after-split folios all have order-0 when split succeeds but in reality get min_order_for_split() order folios and give warnings. Fix it by failing a split if the folio cannot be split to the target order. Rename try_folio_split() to try_folio_split_to_order() to reflect the added new_order parameter. Remove its unused list parameter. [The test poisons LBS folios, which cannot be split to order-0 folios, and also tries to poison all memory. The non split LBS folios take more memory than the test anticipated, leading to OOM. The patch fixed the kernel warning and the test needs some change to avoid OOM.] Link: https://lkml.kernel.org/r/20251017013630.139907-1-ziy@nvidia.com Fixes: e220917fa507 ("mm: split a folio in minimum folio order chunks") Signed-off-by: Zi Yan <ziy(a)nvidia.com> Reported-by: syzbot+e6367ea2fdab6ed46056(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68d2c943.a70a0220.1b52b.02b3.GAE@google.com/ Reviewed-by: Luis Chamberlain <mcgrof(a)kernel.org> Reviewed-by: Pankaj Raghav <p.raghav(a)samsung.com> Reviewed-by: Wei Yang <richard.weiyang(a)gmail.com> Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reviewed-by: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Barry Song <baohua(a)kernel.org> Cc: David Hildenbrand <david(a)redhat.com> Cc: Dev Jain <dev.jain(a)arm.com> Cc: Jane Chu <jane.chu(a)oracle.com> Cc: Lance Yang <lance.yang(a)linux.dev> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Mariano Pache <npache(a)redhat.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Naoya Horiguchi <nao.horiguchi(a)gmail.com> Cc: Ryan Roberts <ryan.roberts(a)arm.com> Cc: Christian Brauner <brauner(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index f327d62fc985..71ac78b9f834 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -376,45 +376,30 @@ bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, int folio_split(struct folio *folio, unsigned int new_order, struct page *page, struct list_head *list); /* - * try_folio_split - try to split a @folio at @page using non uniform split. + * try_folio_split_to_order - try to split a @folio at @page to @new_order using + * non uniform split. * @folio: folio to be split - * @page: split to order-0 at the given page - * @list: store the after-split folios + * @page: split to @new_order at the given page + * @new_order: the target split order * - * Try to split a @folio at @page using non uniform split to order-0, if - * non uniform split is not supported, fall back to uniform split. + * Try to split a @folio at @page using non uniform split to @new_order, if + * non uniform split is not supported, fall back to uniform split. After-split + * folios are put back to LRU list. Use min_order_for_split() to get the lower + * bound of @new_order. * * Return: 0: split is successful, otherwise split failed. */ -static inline int try_folio_split(struct folio *folio, struct page *page, - struct list_head *list) +static inline int try_folio_split_to_order(struct folio *folio, + struct page *page, unsigned int new_order) { - int ret = min_order_for_split(folio); - - if (ret < 0) - return ret; - - if (!non_uniform_split_supported(folio, 0, false)) - return split_huge_page_to_list_to_order(&folio->page, list, - ret); - return folio_split(folio, ret, page, list); + if (!non_uniform_split_supported(folio, new_order, /* warns= */ false)) + return split_huge_page_to_list_to_order(&folio->page, NULL, + new_order); + return folio_split(folio, new_order, page, NULL); } static inline int split_huge_page(struct page *page) { - struct folio *folio = page_folio(page); - int ret = min_order_for_split(folio); - - if (ret < 0) - return ret; - - /* - * split_huge_page() locks the page before splitting and - * expects the same page that has been split to be locked when - * returned. split_folio(page_folio(page)) cannot be used here - * because it converts the page to folio and passes the head - * page to be split. - */ - return split_huge_page_to_list_to_order(page, NULL, ret); + return split_huge_page_to_list_to_order(page, NULL, 0); } void deferred_split_folio(struct folio *folio, bool partially_mapped); @@ -597,14 +582,20 @@ static inline int split_huge_page(struct page *page) return -EINVAL; } +static inline int min_order_for_split(struct folio *folio) +{ + VM_WARN_ON_ONCE_FOLIO(1, folio); + return -EINVAL; +} + static inline int split_folio_to_list(struct folio *folio, struct list_head *list) { VM_WARN_ON_ONCE_FOLIO(1, folio); return -EINVAL; } -static inline int try_folio_split(struct folio *folio, struct page *page, - struct list_head *list) +static inline int try_folio_split_to_order(struct folio *folio, + struct page *page, unsigned int new_order) { VM_WARN_ON_ONCE_FOLIO(1, folio); return -EINVAL; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1d1b74950332..feac4aef7dfb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3653,8 +3653,6 @@ static int __folio_split(struct folio *folio, unsigned int new_order, min_order = mapping_min_folio_order(folio->mapping); if (new_order < min_order) { - VM_WARN_ONCE(1, "Cannot split mapped folio below min-order: %u", - min_order); ret = -EINVAL; goto out; } @@ -3986,12 +3984,7 @@ int min_order_for_split(struct folio *folio) int split_folio_to_list(struct folio *folio, struct list_head *list) { - int ret = min_order_for_split(folio); - - if (ret < 0) - return ret; - - return split_huge_page_to_list_to_order(&folio->page, list, ret); + return split_huge_page_to_list_to_order(&folio->page, list, 0); } /* diff --git a/mm/truncate.c b/mm/truncate.c index 91eb92a5ce4f..9210cf808f5c 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -194,6 +194,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) size_t size = folio_size(folio); unsigned int offset, length; struct page *split_at, *split_at2; + unsigned int min_order; if (pos < start) offset = start - pos; @@ -223,8 +224,9 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) if (!folio_test_large(folio)) return true; + min_order = mapping_min_folio_order(folio->mapping); split_at = folio_page(folio, PAGE_ALIGN_DOWN(offset) / PAGE_SIZE); - if (!try_folio_split(folio, split_at, NULL)) { + if (!try_folio_split_to_order(folio, split_at, min_order)) { /* * try to split at offset + length to make sure folios within * the range can be dropped, especially to avoid memory waste @@ -254,7 +256,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) */ if (folio_test_large(folio2) && folio2->mapping == folio->mapping) - try_folio_split(folio2, split_at2, NULL); + try_folio_split_to_order(folio2, split_at2, min_order); folio_unlock(folio2); out:

1 week, 4 days

2
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Vendor Registration Request 2025/2026

by Etihad Aviation Group

Attn: Sir/Madam, We are interested in your services and invite your company to register for Vendor/Contractor Partnership with Etihad Aviation Group for our 2025/2026 projects. If you wish to participate, please confirm your interest, and we will send the Vendor Questionnaire and EOI. Thank you. Kind Regards, Engr, Tami Hassan, Vendor Procurement & Contracts Shared Services Center Etihad Aviation Group PJSC

1 week, 4 days

1
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FAILED: patch "[PATCH] mm/secretmem: fix use-after-free race in fault handler" 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 6f86d0534fddfbd08687fa0f01479d4226bc3c3d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112020-buddy-bobbed-3c5d@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6f86d0534fddfbd08687fa0f01479d4226bc3c3d Mon Sep 17 00:00:00 2001 From: Lance Yang <lance.yang(a)linux.dev> Date: Fri, 31 Oct 2025 20:09:55 +0800 Subject: [PATCH] mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed. Link: https://lkml.kernel.org/r/20251031120955.92116-1-lance.yang@linux.dev Fixes: 1507f51255c9 ("mm: introduce memfd_secret system call to create "secret" memory areas") Signed-off-by: Lance Yang <lance.yang(a)linux.dev> Reported-by: Google Big Sleep <big-sleep-vuln-reports(a)google.com> Closes: https://lore.kernel.org/linux-mm/CAEXGt5QeDpiHTu3K9tvjUTPqo+d-=wuCNYPa+6sWK… Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/secretmem.c b/mm/secretmem.c index 60137305bc20..b59350daffe3 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -82,13 +82,13 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) __folio_mark_uptodate(folio); err = filemap_add_folio(mapping, folio, offset, gfp); if (unlikely(err)) { - folio_put(folio); /* * If a split of large page was required, it * already happened when we marked the page invalid * which guarantees that this call won't fail */ set_direct_map_default_noflush(folio_page(folio, 0)); + folio_put(folio); if (err == -EEXIST) goto retry;

1 week, 4 days

2
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FAILED: patch "[PATCH] mm/secretmem: fix use-after-free race in fault handler" 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 6f86d0534fddfbd08687fa0f01479d4226bc3c3d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025112021-swept-idealness-9ecb@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6f86d0534fddfbd08687fa0f01479d4226bc3c3d Mon Sep 17 00:00:00 2001 From: Lance Yang <lance.yang(a)linux.dev> Date: Fri, 31 Oct 2025 20:09:55 +0800 Subject: [PATCH] mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed. Link: https://lkml.kernel.org/r/20251031120955.92116-1-lance.yang@linux.dev Fixes: 1507f51255c9 ("mm: introduce memfd_secret system call to create "secret" memory areas") Signed-off-by: Lance Yang <lance.yang(a)linux.dev> Reported-by: Google Big Sleep <big-sleep-vuln-reports(a)google.com> Closes: https://lore.kernel.org/linux-mm/CAEXGt5QeDpiHTu3K9tvjUTPqo+d-=wuCNYPa+6sWK… Acked-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt(a)kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/secretmem.c b/mm/secretmem.c index 60137305bc20..b59350daffe3 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -82,13 +82,13 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) __folio_mark_uptodate(folio); err = filemap_add_folio(mapping, folio, offset, gfp); if (unlikely(err)) { - folio_put(folio); /* * If a split of large page was required, it * already happened when we marked the page invalid * which guarantees that this call won't fail */ set_direct_map_default_noflush(folio_page(folio, 0)); + folio_put(folio); if (err == -EEXIST) goto retry;

1 week, 4 days

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