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[PATCH] USB: OHCI/UHCI: Add soft dependencies on ehci_hcd

by Huacai Chen

Commit 9beeee6584b9aa4f ("USB: EHCI: log a warning if ehci-hcd is not loaded first") said that ehci-hcd should be loaded before ohci-hcd and uhci-hcd. However, commit 05c92da0c52494ca ("usb: ohci/uhci - add soft dependencies on ehci_pci") only makes ohci-pci/uhci-pci depend on ehci- pci, which is not enough and we may still see the warnings in boot log. So fix it by also making ohci-hcd/uhci-hcd depend on ehci-hcd. Cc: stable(a)vger.kernel.org Reported-by: Shengwen Xiao <atzlinux(a)sina.com> Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> --- drivers/usb/host/ohci-hcd.c | 1 + drivers/usb/host/uhci-hcd.c | 1 + 2 files changed, 2 insertions(+) diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c index 9c7f3008646e..549c965b7fbe 100644 --- a/drivers/usb/host/ohci-hcd.c +++ b/drivers/usb/host/ohci-hcd.c @@ -1355,4 +1355,5 @@ static void __exit ohci_hcd_mod_exit(void) clear_bit(USB_OHCI_LOADED, &usb_hcds_loaded); } module_exit(ohci_hcd_mod_exit); +MODULE_SOFTDEP("pre: ehci_hcd"); diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c index 14e6dfef16c6..e1a27d01bdbc 100644 --- a/drivers/usb/host/uhci-hcd.c +++ b/drivers/usb/host/uhci-hcd.c @@ -939,3 +939,4 @@ module_exit(uhci_hcd_cleanup); MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL"); +MODULE_SOFTDEP("pre: ehci_hcd"); -- 2.47.3

15 minutes

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[PATCH v2] gfs2: Fix use-after-free in gfs2_fill_super()

by Ryota Sakamoto

The issue occurs when gfs2_freeze_lock_shared() fails in gfs2_fill_super(). If !sb_rdonly(sb), threads for the quotad and logd were started, however, in the error path for gfs2_freeze_lock_shared(), the threads are not stopped by gfs2_destroy_threads() before jumping to fail_per_node. Introduce fail_threads to handle stopping the threads if the threads were started. Reported-by: syzbot+4cb0d0336db6bc6930e9(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4cb0d0336db6bc6930e9 Fixes: a28dc123fa66 ("gfs2: init system threads before freeze lock") Cc: stable(a)vger.kernel.org Signed-off-by: Ryota Sakamoto <sakamo.ryota(a)gmail.com> --- Changes in v2: - Fix commit message style (imperative mood) as suggested by Markus Elfring. - Add parentheses to function name in subject as suggested by Markus Elfring. - Link to v1: https://lore.kernel.org/r/20251230-fix-use-after-free-gfs2-v1-1-ef0e46db6ec… --- fs/gfs2/ops_fstype.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index e7a88b717991ae3647c1da039636daef7005a7f0..4b5ac1a7050f1fd34e10be4100a2bc381f49c83d 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1269,21 +1269,23 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) error = gfs2_freeze_lock_shared(sdp); if (error) - goto fail_per_node; + goto fail_threads; if (!sb_rdonly(sb)) error = gfs2_make_fs_rw(sdp); if (error) { gfs2_freeze_unlock(sdp); - gfs2_destroy_threads(sdp); fs_err(sdp, "can't make FS RW: %d\n", error); - goto fail_per_node; + goto fail_threads; } gfs2_glock_dq_uninit(&mount_gh); gfs2_online_uevent(sdp); return 0; +fail_threads: + if (!sb_rdonly(sb)) + gfs2_destroy_threads(sdp); fail_per_node: init_per_node(sdp, UNDO); fail_inodes: --- base-commit: 7839932417dd53bb09eb5a585a7a92781dfd7cb2 change-id: 20251230-fix-use-after-free-gfs2-66cfbe23baa8 Best regards, -- Ryota Sakamoto <sakamo.ryota(a)gmail.com>

44 minutes

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[PATCH V3 0/2] LoongArch: KVM: fix "unreliable stack" issue

by Xianglai Li

When starting multi-core loongarch virtualization on loongarch physical machine, loading livepatch on the physical machine will cause an error similar to the following: [ 411.686289] livepatch: klp_try_switch_task: CPU 31/KVM:3116 has an unreliable stack The specific test steps are as follows: 1.Start a multi-core virtual machine on a physical machine 2.Enter the following command on the physical machine to turn on the debug switch: echo "file kernel/livepatch/transition.c +p" > /sys/kernel/debug/\ dynamic_debug/control 3.Load livepatch: modprobe livepatch-sample Through the above steps, similar prints can be viewed in dmesg. The reason for this issue is that the code of the kvm_exc_entry function was copied in the function kvm_loongarch_env_init. When the cpu needs to execute kvm_exc_entry, it will switch to the copied address for execution. The new address of the kvm_exc_entry function cannot be recognized in ORC, which eventually leads to the arch_stack_walk_reliable function returning an error and printing an exception message. To solve the above problems, we directly compile the switch.S file into the kernel instead of the module. In this way, the function kvm_exc_entry will no longer need to be copied. changlog: V3<-V2: 1.Replace the EXPORT_SYMBOL macro declaration symbol with the EXPORT_SYMBOL_FOR_KVM macro 2.Add some comments in kvm_enter_guest 3.Place the correct pc address in era 4.Move .p2align after .text V2<-V1: 1.Rollback the modification of function parameter types such as kvm_save_fpu. In the asm-prototypes.h header file, only the parameter types it depends on are included Cc: Huacai Chen <chenhuacai(a)kernel.org> Cc: WANG Xuerui <kernel(a)xen0n.name> Cc: Tianrui Zhao <zhaotianrui(a)loongson.cn> Cc: Bibo Mao <maobibo(a)loongson.cn> Cc: Charlie Jenkins <charlie(a)rivosinc.com> Cc: Xianglai Li <lixianglai(a)loongson.cn> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Cc: Tiezhu Yang <yangtiezhu(a)loongson.cn> Xianglai Li (2): LoongArch: KVM: Compile the switch.S file directly into the kernel LoongArch: KVM: fix "unreliable stack" issue arch/loongarch/Kbuild | 2 +- arch/loongarch/include/asm/asm-prototypes.h | 21 +++++++++++++ arch/loongarch/include/asm/kvm_host.h | 3 -- arch/loongarch/kvm/Makefile | 2 +- arch/loongarch/kvm/main.c | 35 ++------------------- arch/loongarch/kvm/switch.S | 32 ++++++++++++++++--- 6 files changed, 53 insertions(+), 42 deletions(-) base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 -- 2.39.1

1 hour, 8 minutes

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[PATCH] eisa/pci_eisa: Fix PCI device refcount leak on early init error

by Kaushlendra Kumar

The for_each_pci_dev() loop takes a reference on each PCI device during iteration. When returning early on pci_eisa_init() failure, the reference on 'dev' is not released, causing a resource leak. Add pci_dev_put(dev) before the error return to properly balance the reference count taken by for_each_pci_dev(). Fixes: c5fb301ae83b ("EISA/PCI: Init EISA early, before PNP") Cc: stable(a)vger.kernel.org Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar(a)intel.com> --- drivers/eisa/pci_eisa.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/eisa/pci_eisa.c b/drivers/eisa/pci_eisa.c index 8173e60bb808..8242e9e16ce2 100644 --- a/drivers/eisa/pci_eisa.c +++ b/drivers/eisa/pci_eisa.c @@ -80,8 +80,10 @@ static int __init pci_eisa_init_early(void) for_each_pci_dev(dev) if ((dev->class >> 8) == PCI_CLASS_BRIDGE_EISA) { ret = pci_eisa_init(dev); - if (ret) + if (ret) { + pci_dev_put(dev); return ret; + } } return 0; -- 2.34.1

2 hours, 7 minutes

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[PATCH] mm/damon/core: remove call_control in inactive contexts

by SeongJae Park

If damon_call() is executed against a DAMON context that is not running, the function returns error while keeping the damon_call_control object linked to the context's call_controls list. Let's suppose the object is deallocated after the damon_call(), and yet another damon_call() is executed against the same context. The function tries to add the new damon_call_control object to the call_controls list, which still has the pointer to the previous damon_call_control object, which is deallocated. As a result, use-after-free happens. This can actually be triggered using the DAMON sysfs interface. It is not easily exploitable since it requires the sysfs write permission and making a definitely weird file writes, though. Please refer to the report for more details about the issue reproduction steps. Fix the issue by making damon_call() to cleanup the damon_call_control object before returning the error. Reported-by: JaeJoon Jung <rgbi3307(a)gmail.com> Closes: https://lore.kernel.org/20251224094401.20384-1-rgbi3307@gmail.com Fixes: 42b7491af14c ("mm/damon/core: introduce damon_call()") Cc: <stable(a)vger.kernel.org> # 6.14.x Signed-off-by: SeongJae Park <sj(a)kernel.org> --- mm/damon/core.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 2d3e8006db50..65482a0ce20b 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1442,6 +1442,35 @@ bool damon_is_running(struct damon_ctx *ctx) return running; } +/* + * damon_call_handle_inactive_ctx() - handle DAMON call request that added to + * an inactive context. + * @ctx: The inactive DAMON context. + * @control: Control variable of the call request. + * + * This function is called in a case that @control is added to @ctx but @ctx is + * not running (inactive). See if @ctx handled @control or not, and cleanup + * @control if it was not handled. + * + * Returns 0 if @control was handled by @ctx, negative error code otherwise. + */ +static int damon_call_handle_inactive_ctx( + struct damon_ctx *ctx, struct damon_call_control *control) +{ + struct damon_call_control *c; + + mutex_lock(&ctx->call_controls_lock); + list_for_each_entry(c, &ctx->call_controls, list) { + if (c == control) { + list_del(&control->list); + mutex_unlock(&ctx->call_controls_lock); + return -EINVAL; + } + } + mutex_unlock(&ctx->call_controls_lock); + return 0; +} + /** * damon_call() - Invoke a given function on DAMON worker thread (kdamond). * @ctx: DAMON context to call the function for. @@ -1472,7 +1501,7 @@ int damon_call(struct damon_ctx *ctx, struct damon_call_control *control) list_add_tail(&control->list, &ctx->call_controls); mutex_unlock(&ctx->call_controls_lock); if (!damon_is_running(ctx)) - return -EINVAL; + return damon_call_handle_inactive_ctx(ctx, control); if (control->repeat) return 0; wait_for_completion(&control->completion); base-commit: a100272b3541cb00a5e29fdc16e428234ebfddd1 -- 2.47.3

4 hours, 46 minutes

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FAILED: patch "[PATCH] mm/ksm: fix exec/fork inheritance support for prctl" 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 590c03ca6a3fbb114396673314e2aa483839608b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122924-reproach-foster-4189@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 590c03ca6a3fbb114396673314e2aa483839608b Mon Sep 17 00:00:00 2001 From: xu xin <xu.xin16(a)zte.com.cn> Date: Tue, 7 Oct 2025 18:28:21 +0800 Subject: [PATCH] mm/ksm: fix exec/fork inheritance support for prctl Patch series "ksm: fix exec/fork inheritance", v2. This series fixes exec/fork inheritance. See the detailed description of the issue below. This patch (of 2): Background ========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") introduced MMF_VM_MERGE_ANY for mm->flags, and allowed user to set it by prctl() so that the process's VMAs are forcibly scanned by ksmd. Subsequently, the 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") supported inheriting the MMF_VM_MERGE_ANY flag when a task calls execve(). Finally, commit 3a9e567ca45fb ("mm/ksm: fix ksm exec support for prctl") fixed the issue that ksmd doesn't scan the mm_struct with MMF_VM_MERGE_ANY by adding the mm_slot to ksm_mm_head in __bprm_mm_init(). Problem ======= In some extreme scenarios, however, this inheritance of MMF_VM_MERGE_ANY during exec/fork can fail. For example, when the scanning frequency of ksmd is tuned extremely high, a process carrying MMF_VM_MERGE_ANY may still fail to pass it to the newly exec'd process. This happens because ksm_execve() is executed too early in the do_execve flow (prematurely adding the new mm_struct to the ksm_mm_slot list). As a result, before do_execve completes, ksmd may have already performed a scan and found that this new mm_struct has no VM_MERGEABLE VMAs, thus clearing its MMF_VM_MERGE_ANY flag. Consequently, when the new program executes, the flag MMF_VM_MERGE_ANY inheritance missed. Root reason =========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") clear the flag MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs. Solution ======== Firstly, Don't clear MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs, because perhaps their mm_struct has just been added to ksm_mm_slot list, and its process has not yet officially started running or has not yet performed mmap/brk to allocate anonymous VMAS. Secondly, recheck MMF_VM_MERGEABLE again if a process takes MMF_VM_MERGE_ANY, and create a mm_slot and join it into ksm_scan_list again. Link: https://lkml.kernel.org/r/20251007182504440BJgK8VXRHh8TD7IGSUIY4@zte.com.cn Link: https://lkml.kernel.org/r/20251007182821572h_SoFqYZXEP1mvWI4n9VL@zte.com.cn Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") Fixes: d7597f59d1d3 ("mm: add new api to enable ksm per process") Signed-off-by: xu xin <xu.xin16(a)zte.com.cn> Cc: Stefan Roesch <shr(a)devkernel.io> Cc: David Hildenbrand <david(a)redhat.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Wang Yaxin <wang.yaxin(a)zte.com.cn> Cc: Yang Yang <yang.yang29(a)zte.com.cn> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 067538fc4d58..c982694c987b 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -17,7 +17,7 @@ #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags); -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags); int ksm_enable_merge_any(struct mm_struct *mm); int ksm_disable_merge_any(struct mm_struct *mm); @@ -103,7 +103,7 @@ bool ksm_process_mergeable(struct mm_struct *mm); #else /* !CONFIG_KSM */ -static inline vm_flags_t ksm_vma_flags(const struct mm_struct *mm, +static inline vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { return vm_flags; diff --git a/mm/ksm.c b/mm/ksm.c index cdefba633856..4f672f4f2140 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2712,8 +2712,14 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) spin_unlock(&ksm_mmlist_lock); mm_slot_free(mm_slot_cache, mm_slot); + /* + * Only clear MMF_VM_MERGEABLE. We must not clear + * MMF_VM_MERGE_ANY, because for those MMF_VM_MERGE_ANY process, + * perhaps their mm_struct has just been added to ksm_mm_slot + * list, and its process has not yet officially started running + * or has not yet performed mmap/brk to allocate anonymous VMAS. + */ mm_flags_clear(MMF_VM_MERGEABLE, mm); - mm_flags_clear(MMF_VM_MERGE_ANY, mm); mmap_read_unlock(mm); mmdrop(mm); } else { @@ -2831,12 +2837,20 @@ static int __ksm_del_vma(struct vm_area_struct *vma) * * Returns: @vm_flags possibly updated to mark mergeable. */ -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { if (mm_flags_test(MMF_VM_MERGE_ANY, mm) && - __ksm_should_add_vma(file, vm_flags)) + __ksm_should_add_vma(file, vm_flags)) { vm_flags |= VM_MERGEABLE; + /* + * Generally, the flags here always include MMF_VM_MERGEABLE. + * However, in rare cases, this flag may be cleared by ksmd who + * scans a cycle without finding any mergeable vma. + */ + if (unlikely(!mm_flags_test(MMF_VM_MERGEABLE, mm))) + __ksm_enter(mm); + } return vm_flags; }

5 hours, 16 minutes

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FAILED: patch "[PATCH] mm/ksm: fix exec/fork inheritance support for prctl" 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 590c03ca6a3fbb114396673314e2aa483839608b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122925-designed-overture-2e7d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 590c03ca6a3fbb114396673314e2aa483839608b Mon Sep 17 00:00:00 2001 From: xu xin <xu.xin16(a)zte.com.cn> Date: Tue, 7 Oct 2025 18:28:21 +0800 Subject: [PATCH] mm/ksm: fix exec/fork inheritance support for prctl Patch series "ksm: fix exec/fork inheritance", v2. This series fixes exec/fork inheritance. See the detailed description of the issue below. This patch (of 2): Background ========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") introduced MMF_VM_MERGE_ANY for mm->flags, and allowed user to set it by prctl() so that the process's VMAs are forcibly scanned by ksmd. Subsequently, the 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") supported inheriting the MMF_VM_MERGE_ANY flag when a task calls execve(). Finally, commit 3a9e567ca45fb ("mm/ksm: fix ksm exec support for prctl") fixed the issue that ksmd doesn't scan the mm_struct with MMF_VM_MERGE_ANY by adding the mm_slot to ksm_mm_head in __bprm_mm_init(). Problem ======= In some extreme scenarios, however, this inheritance of MMF_VM_MERGE_ANY during exec/fork can fail. For example, when the scanning frequency of ksmd is tuned extremely high, a process carrying MMF_VM_MERGE_ANY may still fail to pass it to the newly exec'd process. This happens because ksm_execve() is executed too early in the do_execve flow (prematurely adding the new mm_struct to the ksm_mm_slot list). As a result, before do_execve completes, ksmd may have already performed a scan and found that this new mm_struct has no VM_MERGEABLE VMAs, thus clearing its MMF_VM_MERGE_ANY flag. Consequently, when the new program executes, the flag MMF_VM_MERGE_ANY inheritance missed. Root reason =========== commit d7597f59d1d33 ("mm: add new api to enable ksm per process") clear the flag MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs. Solution ======== Firstly, Don't clear MMF_VM_MERGE_ANY when ksmd found no VM_MERGEABLE VMAs, because perhaps their mm_struct has just been added to ksm_mm_slot list, and its process has not yet officially started running or has not yet performed mmap/brk to allocate anonymous VMAS. Secondly, recheck MMF_VM_MERGEABLE again if a process takes MMF_VM_MERGE_ANY, and create a mm_slot and join it into ksm_scan_list again. Link: https://lkml.kernel.org/r/20251007182504440BJgK8VXRHh8TD7IGSUIY4@zte.com.cn Link: https://lkml.kernel.org/r/20251007182821572h_SoFqYZXEP1mvWI4n9VL@zte.com.cn Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") Fixes: d7597f59d1d3 ("mm: add new api to enable ksm per process") Signed-off-by: xu xin <xu.xin16(a)zte.com.cn> Cc: Stefan Roesch <shr(a)devkernel.io> Cc: David Hildenbrand <david(a)redhat.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Wang Yaxin <wang.yaxin(a)zte.com.cn> Cc: Yang Yang <yang.yang29(a)zte.com.cn> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 067538fc4d58..c982694c987b 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -17,7 +17,7 @@ #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags); -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags); int ksm_enable_merge_any(struct mm_struct *mm); int ksm_disable_merge_any(struct mm_struct *mm); @@ -103,7 +103,7 @@ bool ksm_process_mergeable(struct mm_struct *mm); #else /* !CONFIG_KSM */ -static inline vm_flags_t ksm_vma_flags(const struct mm_struct *mm, +static inline vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { return vm_flags; diff --git a/mm/ksm.c b/mm/ksm.c index cdefba633856..4f672f4f2140 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2712,8 +2712,14 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) spin_unlock(&ksm_mmlist_lock); mm_slot_free(mm_slot_cache, mm_slot); + /* + * Only clear MMF_VM_MERGEABLE. We must not clear + * MMF_VM_MERGE_ANY, because for those MMF_VM_MERGE_ANY process, + * perhaps their mm_struct has just been added to ksm_mm_slot + * list, and its process has not yet officially started running + * or has not yet performed mmap/brk to allocate anonymous VMAS. + */ mm_flags_clear(MMF_VM_MERGEABLE, mm); - mm_flags_clear(MMF_VM_MERGE_ANY, mm); mmap_read_unlock(mm); mmdrop(mm); } else { @@ -2831,12 +2837,20 @@ static int __ksm_del_vma(struct vm_area_struct *vma) * * Returns: @vm_flags possibly updated to mark mergeable. */ -vm_flags_t ksm_vma_flags(const struct mm_struct *mm, const struct file *file, +vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vm_flags_t vm_flags) { if (mm_flags_test(MMF_VM_MERGE_ANY, mm) && - __ksm_should_add_vma(file, vm_flags)) + __ksm_should_add_vma(file, vm_flags)) { vm_flags |= VM_MERGEABLE; + /* + * Generally, the flags here always include MMF_VM_MERGEABLE. + * However, in rare cases, this flag may be cleared by ksmd who + * scans a cycle without finding any mergeable vma. + */ + if (unlikely(!mm_flags_test(MMF_VM_MERGEABLE, mm))) + __ksm_enter(mm); + } return vm_flags; }

5 hours, 19 minutes

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FAILED: patch "[PATCH] mm/huge_memory: merge uniform_split_supported() and" failed to apply to 6.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.18-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-6.18.y git checkout FETCH_HEAD git cherry-pick -x 8a0e4bdddd1c998b894d879a1d22f1e745606215 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122925-victory-numeral-2346@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8a0e4bdddd1c998b894d879a1d22f1e745606215 Mon Sep 17 00:00:00 2001 From: Wei Yang <richard.weiyang(a)gmail.com> Date: Thu, 6 Nov 2025 03:41:55 +0000 Subject: [PATCH] mm/huge_memory: merge uniform_split_supported() and non_uniform_split_supported() uniform_split_supported() and non_uniform_split_supported() share significantly similar logic. The only functional difference is that uniform_split_supported() includes an additional check on the requested @new_order. The reason for this check comes from the following two aspects: * some file system or swap cache just supports order-0 folio * the behavioral difference between uniform/non-uniform split The behavioral difference between uniform split and non-uniform: * uniform split splits folio directly to @new_order * non-uniform split creates after-split folios with orders from folio_order(folio) - 1 to new_order. This means for non-uniform split or !new_order split we should check the file system and swap cache respectively. This commit unifies the logic and merge the two functions into a single combined helper, removing redundant code and simplifying the split support checking mechanism. Link: https://lkml.kernel.org/r/20251106034155.21398-3-richard.weiyang@gmail.com Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: "David Hildenbrand (Red Hat)" <david(a)kernel.org> Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com> Cc: Barry Song <baohua(a)kernel.org> Cc: Dev Jain <dev.jain(a)arm.com> Cc: Lance Yang <lance.yang(a)linux.dev> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.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/include/linux/huge_mm.h b/include/linux/huge_mm.h index b74708dc5b5f..19d4a5f52ca2 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -374,10 +374,8 @@ int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list unsigned int new_order, bool unmapped); int min_order_for_split(struct folio *folio); int split_folio_to_list(struct folio *folio, struct list_head *list); -bool uniform_split_supported(struct folio *folio, unsigned int new_order, - bool warns); -bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, - bool warns); +bool folio_split_supported(struct folio *folio, unsigned int new_order, + enum split_type split_type, bool warns); int folio_split(struct folio *folio, unsigned int new_order, struct page *page, struct list_head *list); @@ -408,7 +406,7 @@ static inline int split_huge_page_to_order(struct page *page, unsigned int new_o static inline int try_folio_split_to_order(struct folio *folio, struct page *page, unsigned int new_order) { - if (!non_uniform_split_supported(folio, new_order, /* warns= */ false)) + if (!folio_split_supported(folio, new_order, SPLIT_TYPE_NON_UNIFORM, /* warns= */ false)) return split_huge_page_to_order(&folio->page, new_order); return folio_split(folio, new_order, page, NULL); } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4118f330c55e..d79a4bb363de 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3593,8 +3593,8 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, return 0; } -bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, - bool warns) +bool folio_split_supported(struct folio *folio, unsigned int new_order, + enum split_type split_type, bool warns) { if (folio_test_anon(folio)) { /* order-1 is not supported for anonymous THP. */ @@ -3602,48 +3602,41 @@ bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, "Cannot split to order-1 folio"); if (new_order == 1) return false; - } else if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && - !mapping_large_folio_support(folio->mapping)) { - /* - * No split if the file system does not support large folio. - * Note that we might still have THPs in such mappings due to - * CONFIG_READ_ONLY_THP_FOR_FS. But in that case, the mapping - * does not actually support large folios properly. - */ - VM_WARN_ONCE(warns, - "Cannot split file folio to non-0 order"); - return false; - } - - /* Only swapping a whole PMD-mapped folio is supported */ - if (folio_test_swapcache(folio)) { - VM_WARN_ONCE(warns, - "Cannot split swapcache folio to non-0 order"); - return false; - } - - return true; -} - -/* See comments in non_uniform_split_supported() */ -bool uniform_split_supported(struct folio *folio, unsigned int new_order, - bool warns) -{ - if (folio_test_anon(folio)) { - VM_WARN_ONCE(warns && new_order == 1, - "Cannot split to order-1 folio"); - if (new_order == 1) - return false; - } else if (new_order) { + } else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) { if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !mapping_large_folio_support(folio->mapping)) { + /* + * We can always split a folio down to a single page + * (new_order == 0) uniformly. + * + * For any other scenario + * a) uniform split targeting a large folio + * (new_order > 0) + * b) any non-uniform split + * we must confirm that the file system supports large + * folios. + * + * Note that we might still have THPs in such + * mappings, which is created from khugepaged when + * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that + * case, the mapping does not actually support large + * folios properly. + */ VM_WARN_ONCE(warns, "Cannot split file folio to non-0 order"); return false; } } - if (new_order && folio_test_swapcache(folio)) { + /* + * swapcache folio could only be split to order 0 + * + * non-uniform split creates after-split folios with orders from + * folio_order(folio) - 1 to new_order, making it not suitable for any + * swapcache folio split. Only uniform split to order-0 can be used + * here. + */ + if ((split_type == SPLIT_TYPE_NON_UNIFORM || new_order) && folio_test_swapcache(folio)) { VM_WARN_ONCE(warns, "Cannot split swapcache folio to non-0 order"); return false; @@ -3711,11 +3704,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, if (new_order >= old_order) return -EINVAL; - if (split_type == SPLIT_TYPE_UNIFORM && !uniform_split_supported(folio, new_order, true)) - return -EINVAL; - - if (split_type == SPLIT_TYPE_NON_UNIFORM && - !non_uniform_split_supported(folio, new_order, true)) + if (!folio_split_supported(folio, new_order, split_type, /* warn = */ true)) return -EINVAL; is_hzp = is_huge_zero_folio(folio);

5 hours, 19 minutes

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FAILED: patch "[PATCH] erofs: fix unexpected EIO under memory pressure" failed to apply to 6.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.18-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-6.18.y git checkout FETCH_HEAD git cherry-pick -x 4012d78562193ef5eb613bad4b0c0fa187637cfe # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122915-kitchen-june-49ec@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4012d78562193ef5eb613bad4b0c0fa187637cfe Mon Sep 17 00:00:00 2001 From: Junbeom Yeom <junbeom.yeom(a)samsung.com> Date: Fri, 19 Dec 2025 21:40:31 +0900 Subject: [PATCH] erofs: fix unexpected EIO under memory pressure erofs readahead could fail with ENOMEM under the memory pressure because it tries to alloc_page with GFP_NOWAIT | GFP_NORETRY, while GFP_KERNEL for a regular read. And if readahead fails (with non-uptodate folios), the original request will then fall back to synchronous read, and `.read_folio()` should return appropriate errnos. However, in scenarios where readahead and read operations compete, read operation could return an unintended EIO because of an incorrect error propagation. To resolve this, this patch modifies the behavior so that, when the PCL is for read(which means pcl.besteffort is true), it attempts actual decompression instead of propagating the privios error except initial EIO. - Page size: 4K - The original size of FileA: 16K - Compress-ratio per PCL: 50% (Uncompressed 8K -> Compressed 4K) [page0, page1] [page2, page3] [PCL0]---------[PCL1] - functions declaration: . pread(fd, buf, count, offset) . readahead(fd, offset, count) - Thread A tries to read the last 4K - Thread B tries to do readahead 8K from 4K - RA, besteffort == false - R, besteffort == true <process A> <process B> pread(FileA, buf, 4K, 12K) do readahead(page3) // failed with ENOMEM wait_lock(page3) if (!uptodate(page3)) goto do_read readahead(FileA, 4K, 8K) // Here create PCL-chain like below: // [null, page1] [page2, null] // [PCL0:RA]-----[PCL1:RA] ... do read(page3) // found [PCL1:RA] and add page3 into it, // and then, change PCL1 from RA to R ... // Now, PCL-chain is as below: // [null, page1] [page2, page3] // [PCL0:RA]-----[PCL1:R] // try to decompress PCL-chain... z_erofs_decompress_queue err = 0; // failed with ENOMEM, so page 1 // only for RA will not be uptodated. // it's okay. err = decompress([PCL0:RA], err) // However, ENOMEM propagated to next // PCL, even though PCL is not only // for RA but also for R. As a result, // it just failed with ENOMEM without // trying any decompression, so page2 // and page3 will not be uptodated. ** BUG HERE ** --> err = decompress([PCL1:R], err) return err as ENOMEM ... wait_lock(page3) if (!uptodate(page3)) return EIO <-- Return an unexpected EIO! ... Fixes: 2349d2fa02db ("erofs: sunset unneeded NOFAILs") Cc: stable(a)vger.kernel.org Reviewed-by: Jaewook Kim <jw5454.kim(a)samsung.com> Reviewed-by: Sungjong Seo <sj1557.seo(a)samsung.com> Signed-off-by: Junbeom Yeom <junbeom.yeom(a)samsung.com> Reviewed-by: Gao Xiang <hsiangkao(a)linux.alibaba.com> Signed-off-by: Gao Xiang <hsiangkao(a)linux.alibaba.com> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 65da21504632..3d31f7840ca0 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1262,7 +1262,7 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_backend *be, bool *overlapped) return err; } -static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err) +static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, bool eio) { struct erofs_sb_info *const sbi = EROFS_SB(be->sb); struct z_erofs_pcluster *pcl = be->pcl; @@ -1270,7 +1270,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err) const struct z_erofs_decompressor *alg = z_erofs_decomp[pcl->algorithmformat]; bool try_free = true; - int i, j, jtop, err2; + int i, j, jtop, err2, err = eio ? -EIO : 0; struct page *page; bool overlapped; const char *reason; @@ -1413,12 +1413,12 @@ static int z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io, .pcl = io->head, }; struct z_erofs_pcluster *next; - int err = io->eio ? -EIO : 0; + int err = 0; for (; be.pcl != Z_EROFS_PCLUSTER_TAIL; be.pcl = next) { DBG_BUGON(!be.pcl); next = READ_ONCE(be.pcl->next); - err = z_erofs_decompress_pcluster(&be, err) ?: err; + err = z_erofs_decompress_pcluster(&be, io->eio) ?: err; } return err; }

6 hours

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[PATCH 5.15.y RESEND] KVM: arm64: sys_regs: disable -Wuninitialized-const-pointer warning

by Justin Stitt

A new warning in Clang 22 [1] complains that @clidr passed to get_clidr_el1() is an uninitialized const pointer. get_clidr_el1() doesn't really care since it casts away the const-ness anyways -- it is a false positive. | ../arch/arm64/kvm/sys_regs.c:2838:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] | 2838 | get_clidr_el1(NULL, &clidr); /* Ugly... */ | | ^~~~~ This patch isn't needed for anything past 6.1 as this code section was reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache configuration"). Since there is no upstream equivalent, this patch just needs to be applied to 5.15. Disable this warning for sys_regs.o with an iron fist as it doesn't make sense to waste maintainer's time or potentially break builds by backporting large changelists from 6.2+. Cc: stable(a)vger.kernel.org Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d44… [1] Reviewed-by: Nathan Chancellor <nathan(a)kernel.org> Signed-off-by: Justin Stitt <justinstitt(a)google.com> --- Resending this with Nathan's RB tag, an updated commit log and better recipients from checkpatch.pl. I'm also sending a similar patch resend for 6.1. --- arch/arm64/kvm/Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 989bb5dad2c8..109cca425d3e 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -25,3 +25,6 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \ vgic/vgic-its.o vgic/vgic-debug.o kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o + +# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning +CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer) --- base-commit: 8bb7eca972ad531c9b149c0a51ab43a417385813 change-id: 20250728-b4-stable-disable-uninit-ptr-warn-5-15-c0c9db3df206 Best regards, -- Justin Stitt <justinstitt(a)google.com>

6 hours, 6 minutes

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