The patch titled Subject: mm: vmalloc: avoid racy handling of debugobjects in vunmap has been added to the -mm tree. Its filename is mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Chintan Pandya <cpandya@xxxxxxxxxxxxxx> Subject: mm: vmalloc: avoid racy handling of debugobjects in vunmap Currently, __vunmap flow is, 1) Release the VM area 2) Free the debug objects corresponding to that vm area. This leave some race window open. 1) Release the VM area 1.5) Some other client gets the same vm area 1.6) This client allocates new debug objects on the same vm area 2) Free the debug objects corresponding to this vm area. Here, we actually free 'other' client's debug objects. Fix this by freeing the debug objects first and then releasing the VM area. Link: http://lkml.kernel.org/r/1523961828-9485-2-git-send-email-cpandya@xxxxxxxxxxxxxx Signed-off-by: Chintan Pandya <cpandya@xxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Byungchul Park <byungchul.park@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Florian Fainelli <f.fainelli@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Laura Abbott <labbott@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxx> Cc: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff -puN mm/vmalloc.c~mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap mm/vmalloc.c --- a/mm/vmalloc.c~mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap +++ a/mm/vmalloc.c @@ -1500,7 +1500,7 @@ static void __vunmap(const void *addr, i addr)) return; - area = remove_vm_area(addr); + area = find_vmap_area((unsigned long)addr)->vm; if (unlikely(!area)) { WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n", addr); @@ -1510,6 +1510,7 @@ static void __vunmap(const void *addr, i debug_check_no_locks_freed(addr, get_vm_area_size(area)); debug_check_no_obj_freed(addr, get_vm_area_size(area)); + remove_vm_area(addr); if (deallocate_pages) { int i; _ Patches currently in -mm which might be from cpandya@xxxxxxxxxxxxxx are mm-vmalloc-clean-up-vunmap-to-avoid-pgtable-ops-twice.patch mm-vmalloc-avoid-racy-handling-of-debugobjects-in-vunmap.patch mm-vmalloc-pass-proper-vm_start-into-debugobjects.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html