From 4080ef1579b2413435413988d14ac8c68e4d42c8 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Tue, 29 Oct 2024 18:11:45 +0000 Subject: mm: unconditionally close VMAs on error 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/vma.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/vma.h') diff --git a/mm/vma.h b/mm/vma.h index 55457cb68200..75558b5e9c8c 100644 --- a/mm/vma.h +++ b/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(struct vma_munmap_struct *vms, 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 *vmi, struct mm_struct *mm, 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); -- cgit v1.2.3