From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDB71387357 for ; Tue, 31 Mar 2026 18:29:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774981788; cv=none; b=pRby2+E1Dal1X8Vpi+3kl3KFqw1e0bZTfGV4o35WzMWaHKgrRt+ibwL790e6ma8na+UjCtKbyelTvF9//GEI+c+Y6wX3pgPwZVH6AiBMkEecB+aNgxMK8Guezu8rgpufVzahjh1ioplnFCwtC8VcA0dz/XcBoexeVSFdcQr5RaU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774981788; c=relaxed/simple; bh=XVSe7/3U3/dqWtTk5dAzERJ/lHcfUuquWWJbklpZ130=; h=Date:To:From:Subject:Message-Id; b=qc3TS0rXI7LZUtlbuN0fnVP8F9NJtSmMeGf8A6xwHZqY2jZEv0wHeruIkG5J17cA3xVYuw3YRtVk3KvzRtPM3h3CBKQKckcK8ai3FLtCjHXZrrzNYIPvcoMVpZPF2ddP6h9ozt2+AZXlNqlRRa7hEMA+ErphkDa9RDgkqN8ooyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=YXlEyQqr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="YXlEyQqr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4ECCBC19423; Tue, 31 Mar 2026 18:29:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1774981788; bh=XVSe7/3U3/dqWtTk5dAzERJ/lHcfUuquWWJbklpZ130=; h=Date:To:From:Subject:From; b=YXlEyQqrxo6utSAA/N1prBym+TFcUTib701b6lioI0bxfNpb/RvY/2CRXyfkhZ3N6 815uI9CP9xgX0gUgTNWLNMqSkASGb+qyNHQVbEV3NlhIKD3Ioz62IHOMi4ukrUXDWW 9Jo9nV31kEbHHzAV1xaMQXx6oXe1ykda+VcLEJag= Date: Tue, 31 Mar 2026 11:29:47 -0700 To: mm-commits@vger.kernel.org,surenb@google.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-vma-use-vma_start_write_killable-in-vma-operations.patch removed from -mm tree Message-Id: <20260331182948.4ECCBC19423@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/vma: use vma_start_write_killable() in vma operations has been removed from the -mm tree. Its filename was mm-vma-use-vma_start_write_killable-in-vma-operations.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Suren Baghdasaryan Subject: mm/vma: use vma_start_write_killable() in vma operations Date: Fri, 27 Mar 2026 13:54:55 -0700 Replace vma_start_write() with vma_start_write_killable(), improving reaction time to the kill signal. Replace vma_start_write() calls when we operate on VMAs. To propagate errors from vma_merge_existing_range() and vma_expand() we fake an ENOMEM error when we fail due to a pending fatal signal. This is a temporary workaround. Fixing this requires some refactoring and will be done separately in the future. In a number of places we now lock VMA earlier than before to avoid doing work and undoing it later if a fatal signal is pending. This is safe because the moves are happening within sections where we already hold the mmap_write_lock, so the moves do not change the locking order relative to other kernel locks. Link: https://lkml.kernel.org/r/20260327205457.604224-5-surenb@google.com Signed-off-by: Suren Baghdasaryan Suggested-by: Matthew Wilcox Cc: Alexander Gordeev Cc: Alistair Popple Cc: Baolin Wang Cc: Barry Song Cc: Byungchul Park Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Dev Jain Cc: Gerald Schaefer Cc: Gregory Price Cc: Heiko Carstens Cc: "Huang, Ying" Cc: Jann Horn Cc: Janosch Frank Cc: Joshua Hahn Cc: Kees Cook Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Lorenzo Stoakes (Oracle) Cc: Madhavan Srinivasan Cc: Matthew Brost Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Nico Pache Cc: Pedro Falcato Cc: Rakie Kim Cc: Ritesh Harjani (IBM) Cc: Ryan Roberts Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/vma.c | 146 +++++++++++++++++++++++++++++++++++++----------- mm/vma_exec.c | 6 + 2 files changed, 117 insertions(+), 35 deletions(-) --- a/mm/vma.c~mm-vma-use-vma_start_write_killable-in-vma-operations +++ a/mm/vma.c @@ -524,6 +524,21 @@ __split_vma(struct vma_iterator *vmi, st new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); } + /* + * Lock VMAs before cloning to avoid extra work if fatal signal + * is pending. + */ + err = vma_start_write_killable(vma); + if (err) + goto out_free_vma; + /* + * Locking a new detached VMA will always succeed but it's just a + * detail of the current implementation, so handle it all the same. + */ + err = vma_start_write_killable(new); + if (err) + goto out_free_vma; + err = -ENOMEM; vma_iter_config(vmi, new->vm_start, new->vm_end); if (vma_iter_prealloc(vmi, new)) @@ -543,9 +558,6 @@ __split_vma(struct vma_iterator *vmi, st if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); - vma_start_write(vma); - vma_start_write(new); - init_vma_prep(&vp, vma); vp.insert = new; vma_prepare(&vp); @@ -900,12 +912,22 @@ static __must_check struct vm_area_struc } /* No matter what happens, we will be adjusting middle. */ - vma_start_write(middle); + err = vma_start_write_killable(middle); + if (err) { + /* Ensure error propagates. */ + vmg->give_up_on_oom = false; + goto abort; + } if (merge_right) { vma_flags_t next_sticky; - vma_start_write(next); + err = vma_start_write_killable(next); + if (err) { + /* Ensure error propagates. */ + vmg->give_up_on_oom = false; + goto abort; + } vmg->target = next; next_sticky = vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); vma_flags_set_mask(&sticky_flags, next_sticky); @@ -914,7 +936,12 @@ static __must_check struct vm_area_struc if (merge_left) { vma_flags_t prev_sticky; - vma_start_write(prev); + err = vma_start_write_killable(prev); + if (err) { + /* Ensure error propagates. */ + vmg->give_up_on_oom = false; + goto abort; + } vmg->target = prev; prev_sticky = vma_flags_and_mask(&prev->flags, VMA_STICKY_FLAGS); @@ -1170,10 +1197,18 @@ int vma_expand(struct vma_merge_struct * vma_flags_t sticky_flags = vma_flags_and_mask(&vmg->vma_flags, VMA_STICKY_FLAGS); vma_flags_t target_sticky; - int err = 0; + int err; mmap_assert_write_locked(vmg->mm); - vma_start_write(target); + err = vma_start_write_killable(target); + if (err) { + /* + * Override VMA_MERGE_NOMERGE to prevent callers from + * falling back to a new VMA allocation. + */ + vmg->state = VMA_MERGE_ERROR_NOMEM; + return err; + } target_sticky = vma_flags_and_mask(&target->flags, VMA_STICKY_FLAGS); @@ -1201,6 +1236,19 @@ int vma_expand(struct vma_merge_struct * * we don't need to account for vmg->give_up_on_mm here. */ if (remove_next) { + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + err = vma_start_write_killable(next); + if (err) { + /* + * Override VMA_MERGE_NOMERGE to prevent callers from + * falling back to a new VMA allocation. + */ + vmg->state = VMA_MERGE_ERROR_NOMEM; + return err; + } err = dup_anon_vma(target, next, &anon_dup); if (err) return err; @@ -1214,7 +1262,6 @@ int vma_expand(struct vma_merge_struct * if (remove_next) { vma_flags_t next_sticky; - vma_start_write(next); vmg->__remove_next = true; next_sticky = vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); @@ -1252,9 +1299,14 @@ int vma_shrink(struct vma_iterator *vmi, unsigned long start, unsigned long end, pgoff_t pgoff) { struct vma_prepare vp; + int err; WARN_ON((vma->vm_start != start) && (vma->vm_end != end)); + err = vma_start_write_killable(vma); + if (err) + return err; + if (vma->vm_start < start) vma_iter_config(vmi, vma->vm_start, start); else @@ -1263,8 +1315,6 @@ int vma_shrink(struct vma_iterator *vmi, if (vma_iter_prealloc(vmi, NULL)) return -ENOMEM; - vma_start_write(vma); - init_vma_prep(&vp, vma); vma_prepare(&vp); vma_adjust_trans_huge(vma, start, end, NULL); @@ -1453,7 +1503,9 @@ static int vms_gather_munmap_vmas(struct if (error) goto end_split_failed; } - vma_start_write(next); + error = vma_start_write_killable(next); + if (error) + goto munmap_gather_failed; mas_set(mas_detach, vms->vma_count++); error = mas_store_gfp(mas_detach, next, GFP_KERNEL); if (error) @@ -1848,12 +1900,16 @@ static void vma_link_file(struct vm_area static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) { VMA_ITERATOR(vmi, mm, 0); + int err; + + err = vma_start_write_killable(vma); + if (err) + return err; vma_iter_config(&vmi, vma->vm_start, vma->vm_end); if (vma_iter_prealloc(&vmi, vma)) return -ENOMEM; - vma_start_write(vma); vma_iter_store_new(&vmi, vma); vma_link_file(vma, /* hold_rmap_lock= */false); mm->map_count++; @@ -2239,9 +2295,8 @@ int mm_take_all_locks(struct mm_struct * * is reached. */ for_each_vma(vmi, vma) { - if (signal_pending(current)) + if (signal_pending(current) || vma_start_write_killable(vma)) goto out_unlock; - vma_start_write(vma); } vma_iter_init(&vmi, mm, 0); @@ -2540,8 +2595,8 @@ static int __mmap_new_vma(struct mmap_st struct mmap_action *action) { struct vma_iterator *vmi = map->vmi; - int error = 0; struct vm_area_struct *vma; + int error; /* * Determine the object being mapped and call the appropriate @@ -2552,6 +2607,14 @@ static int __mmap_new_vma(struct mmap_st if (!vma) return -ENOMEM; + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + error = vma_start_write_killable(vma); + if (error) + goto free_vma; + vma_iter_config(vmi, map->addr, map->end); vma_set_range(vma, map->addr, map->end, map->pgoff); vma->flags = map->vma_flags; @@ -2582,8 +2645,6 @@ static int __mmap_new_vma(struct mmap_st WARN_ON_ONCE(!arch_validate_flags(map->vm_flags)); #endif - /* Lock the VMA since it is modified after insertion into VMA tree */ - vma_start_write(vma); vma_iter_store_new(vmi, vma); map->mm->map_count++; vma_link_file(vma, action->hide_from_rmap_until_complete); @@ -2878,6 +2939,7 @@ int do_brk_flags(struct vma_iterator *vm unsigned long addr, unsigned long len, vma_flags_t vma_flags) { struct mm_struct *mm = current->mm; + int err; /* * Check against address space limits by the changed size @@ -2910,24 +2972,33 @@ int do_brk_flags(struct vma_iterator *vm if (vma_merge_new_range(&vmg)) goto out; - else if (vmg_nomem(&vmg)) + if (vmg_nomem(&vmg)) { + err = -ENOMEM; goto unacct_fail; + } } if (vma) vma_iter_next_range(vmi); /* create a vma struct for an anonymous mapping */ vma = vm_area_alloc(mm); - if (!vma) + if (!vma) { + err = -ENOMEM; goto unacct_fail; + } vma_set_anonymous(vma); vma_set_range(vma, addr, addr + len, addr >> PAGE_SHIFT); vma->flags = vma_flags; vma->vm_page_prot = vm_get_page_prot(vma_flags_to_legacy(vma_flags)); - vma_start_write(vma); - if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) + if (vma_start_write_killable(vma)) { + err = -EINTR; + goto vma_lock_fail; + } + if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) { + err = -ENOMEM; goto mas_store_fail; + } mm->map_count++; validate_mm(mm); @@ -2942,10 +3013,11 @@ out: return 0; mas_store_fail: +vma_lock_fail: vm_area_free(vma); unacct_fail: vm_unacct_memory(len >> PAGE_SHIFT); - return -ENOMEM; + return err; } /** @@ -3112,8 +3184,8 @@ int expand_upwards(struct vm_area_struct struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *next; unsigned long gap_addr; - int error = 0; VMA_ITERATOR(vmi, mm, vma->vm_start); + int error; if (!vma_test(vma, VMA_GROWSUP_BIT)) return -EFAULT; @@ -3149,12 +3221,14 @@ int expand_upwards(struct vm_area_struct /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) { - vma_iter_free(&vmi); - return -ENOMEM; + error = -ENOMEM; + goto vma_prep_fail; } /* Lock the VMA before expanding to prevent concurrent page faults */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto vma_lock_fail; /* We update the anon VMA tree. */ anon_vma_lock_write(vma->anon_vma); @@ -3183,8 +3257,10 @@ int expand_upwards(struct vm_area_struct } } anon_vma_unlock_write(vma->anon_vma); - vma_iter_free(&vmi); validate_mm(mm); +vma_lock_fail: +vma_prep_fail: + vma_iter_free(&vmi); return error; } #endif /* CONFIG_STACK_GROWSUP */ @@ -3197,8 +3273,8 @@ int expand_downwards(struct vm_area_stru { struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *prev; - int error = 0; VMA_ITERATOR(vmi, mm, vma->vm_start); + int error; if (!vma_test(vma, VMA_GROWSDOWN_BIT)) return -EFAULT; @@ -3228,12 +3304,14 @@ int expand_downwards(struct vm_area_stru /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) { - vma_iter_free(&vmi); - return -ENOMEM; + error = -ENOMEM; + goto vma_prep_fail; } /* Lock the VMA before expanding to prevent concurrent page faults */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto vma_lock_fail; /* We update the anon VMA tree. */ anon_vma_lock_write(vma->anon_vma); @@ -3263,8 +3341,10 @@ int expand_downwards(struct vm_area_stru } } anon_vma_unlock_write(vma->anon_vma); - vma_iter_free(&vmi); validate_mm(mm); +vma_lock_fail: +vma_prep_fail: + vma_iter_free(&vmi); return error; } --- a/mm/vma_exec.c~mm-vma-use-vma_start_write_killable-in-vma-operations +++ a/mm/vma_exec.c @@ -41,6 +41,7 @@ int relocate_vma_down(struct vm_area_str struct vm_area_struct *next; struct mmu_gather tlb; PAGETABLE_MOVE(pmc, vma, vma, old_start, new_start, length); + int err; BUG_ON(new_start > new_end); @@ -56,8 +57,9 @@ int relocate_vma_down(struct vm_area_str * cover the whole range: [new_start, old_end) */ vmg.target = vma; - if (vma_expand(&vmg)) - return -ENOMEM; + err = vma_expand(&vmg); + if (err) + return err; /* * move the page tables downwards, on failure we rely on _ Patches currently in -mm which might be from surenb@google.com are mm-use-vma_start_write_killable-in-process_vma_walk_lock.patch kvm-ppc-use-vma_start_write_killable-in-kvmppc_memslot_page_merge.patch mm-vmscan-prevent-mglru-reclaim-from-pinning-address-space.patch