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 97BA511CAF; Wed, 30 Oct 2024 00:36:03 +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=1730248563; cv=none; b=URWMe1oFtwJDSRE0Co1JA6C1vWqv5CcQqcjFMqxdZaxSxBdrUKSojWVmVhbk3FQ13FLJcZcObx8F7puhDWdyc3JU9dRZh2et36J1tmNtG1mazdLDz6EPzh5Bs2ZImoL+hVMlkd8d9fJfNj4g3CvcoVLiSxDJskmiZlSyi+a94g4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730248563; c=relaxed/simple; bh=8a7ZNqaQpFxP3KYmn3w2wHPbT98i+MFtEX4aYnqIWQ8=; h=Date:To:From:Subject:Message-Id; b=V6wkZI07zVSLWxgZkP2E10WFAWmXOR1qcYKPYfYo/11CmpN2oZCaFM8Kao4NOEIQ+NM2CWoGZRVgGBVcHzgx4Sz/aYEeyO3f3KzgHZNQAk5qyfWiQQuiyFq6lk9f/td4LtWQZy9w8f5160qx1xFMRa3r+vrrNLMpQe1BW6HawpA= 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=w86d4rzT; 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="w86d4rzT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1089EC4CECD; Wed, 30 Oct 2024 00:36:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1730248563; bh=8a7ZNqaQpFxP3KYmn3w2wHPbT98i+MFtEX4aYnqIWQ8=; h=Date:To:From:Subject:From; b=w86d4rzT+QioWrwU6nt8IgDwEIlDnzlGB9nQmd2S1uacX+VSLelAqGj8lPt+BXc22 kbOfKJkaU1aPN48HkejmHLCmio1QZ7voIZE+Y+IorRJ/T/w9flxaMgc8gJQf2sX+l6 MgZ0IQM4QKnMRjuz20pbJfc8reWneOYL0DeT52vY= Date: Tue, 29 Oct 2024 17:36:02 -0700 To: mm-commits@vger.kernel.org,will@kernel.org,vbabka@suse.cz,torvalds@linux-foundation.org,stable@vger.kernel.org,peterx@redhat.com,Liam.Howlett@oracle.com,jannh@google.com,James.Bottomley@HansenPartnership.com,deller@gmx.de,davem@davemloft.net,catalin.marinas@arm.com,broonie@kernel.org,andreas@gaisler.com,lorenzo.stoakes@oracle.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-unconditionally-close-vmas-on-error.patch added to mm-hotfixes-unstable branch Message-Id: <20241030003603.1089EC4CECD@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: unconditionally close VMAs on error has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-unconditionally-close-vmas-on-error.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-unconditionally-close-vmas-on-error.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Lorenzo Stoakes Subject: mm: unconditionally close VMAs on error Date: Tue, 29 Oct 2024 18:11:45 +0000 Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Reported-by: Jann Horn Reviewed-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Reviewed-by: Jann Horn Cc: Andreas Larsson Cc: Catalin Marinas Cc: David S. Miller Cc: Helge Deller Cc: James E.J. Bottomley Cc: Linus Torvalds Cc: Mark Brown Cc: Peter Xu Cc: Will Deacon Cc: Signed-off-by: Andrew Morton --- mm/internal.h | 18 ++++++++++++++++++ mm/mmap.c | 5 ++--- mm/nommu.c | 3 +-- mm/vma.c | 14 +++++--------- mm/vma.h | 4 +--- 5 files changed, 27 insertions(+), 17 deletions(-) --- a/mm/internal.h~mm-unconditionally-close-vmas-on-error +++ a/mm/internal.h @@ -135,6 +135,24 @@ static inline int mmap_file(struct file return err; } +/* + * If the VMA has a close hook then close it, and since closing it might leave + * it in an inconsistent state which makes the use of any hooks suspect, clear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + } +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ --- a/mm/mmap.c~mm-unconditionally-close-vmas-on-error +++ a/mm/mmap.c @@ -1573,8 +1573,7 @@ expanded: return addr; close_and_free_vma: - if (file && !vms.closed_vm_ops && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -1934,7 +1933,7 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true, /* closed = */ false); + remove_vma(vma, /* unreachable = */ true); count++; cond_resched(); vma = vma_next(&vmi); --- a/mm/nommu.c~mm-unconditionally-close-vmas-on-error +++ a/mm/nommu.c @@ -589,8 +589,7 @@ static int delete_vma_from_mm(struct vm_ */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region); --- a/mm/vma.c~mm-unconditionally-close-vmas-on-error +++ a/mm/vma.c @@ -323,11 +323,10 @@ static bool can_vma_merge_right(struct v /* * Close a vm structure and free it. */ -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed) +void remove_vma(struct vm_area_struct *vma, bool unreachable) { might_sleep(); - if (!closed && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); @@ -1115,9 +1114,7 @@ void vms_clean_up_area(struct vma_munmap vms_clear_ptes(vms, mas_detach, true); mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); - vms->closed_vm_ops = true; + vma_close(vma); } /* @@ -1160,7 +1157,7 @@ void vms_complete_munmap_vmas(struct vma /* Remove and clean up vmas */ mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - remove_vma(vma, /* = */ false, vms->closed_vm_ops); + remove_vma(vma, /* unreachable = */ false); vm_unacct_memory(vms->nr_accounted); validate_mm(mm); @@ -1684,8 +1681,7 @@ struct vm_area_struct *copy_vma(struct v return new_vma; out_vma_link: - if (new_vma->vm_ops && new_vma->vm_ops->close) - new_vma->vm_ops->close(new_vma); + vma_close(new_vma); if (new_vma->vm_file) fput(new_vma->vm_file); --- a/mm/vma.h~mm-unconditionally-close-vmas-on-error +++ a/mm/vma.h @@ -42,7 +42,6 @@ struct vma_munmap_struct { int vma_count; /* Number of vmas that will be removed */ bool unlock; /* Unlock after the munmap */ bool clear_ptes; /* If there are outstanding PTE to be cleared */ - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ /* 1 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ @@ -198,7 +197,6 @@ static inline void init_vma_munmap(struc vms->unmap_start = FIRST_USER_ADDRESS; vms->unmap_end = USER_PGTABLES_CEILING; vms->clear_ptes = false; - vms->closed_vm_ops = false; } #endif @@ -269,7 +267,7 @@ int do_vmi_munmap(struct vma_iterator *v unsigned long start, size_t len, struct list_head *uf, bool unlock); -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed); +void remove_vma(struct vm_area_struct *vma, bool unreachable); void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next); _ Patches currently in -mm which might be from lorenzo.stoakes@oracle.com are mm-avoid-unsafe-vma-hook-invocation-when-error-arises-on-mmap-hook.patch mm-unconditionally-close-vmas-on-error.patch mm-refactor-map_deny_write_exec.patch mm-refactor-arch_calc_vm_flag_bits-and-arm64-mte-handling.patch mm-resolve-faulty-mmap_region-error-path-behaviour.patch selftests-mm-add-pkey_sighandler_xx-hugetlb_dio-to-gitignore.patch mm-refactor-mm_access-to-not-return-null.patch mm-refactor-mm_access-to-not-return-null-fix.patch mm-madvise-unrestrict-process_madvise-for-current-process.patch maple_tree-do-not-hash-pointers-on-dump-in-debug-mode.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems-fix.patch tools-testing-add-additional-vma_internalh-stubs.patch mm-isolate-mmap-internal-logic-to-mm-vmac.patch mm-refactor-__mmap_region.patch mm-remove-unnecessary-reset-state-logic-on-merge-new-vma.patch mm-defer-second-attempt-at-merge-on-mmap.patch mm-defer-second-attempt-at-merge-on-mmap-fix.patch mm-pagewalk-add-the-ability-to-install-ptes.patch mm-add-pte_marker_guard-pte-marker.patch mm-madvise-implement-lightweight-guard-page-mechanism.patch tools-testing-update-tools-uapi-header-for-mman-commonh.patch selftests-mm-add-self-tests-for-guard-page-feature.patch