]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: vmalloc: avoid racy handling of debugobjects in vunmap
authorChintan Pandya <cpandya@codeaurora.org>
Fri, 8 Jun 2018 00:06:50 +0000 (17:06 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 8 Jun 2018 00:34:35 +0000 (17:34 -0700)
commitf3c01d2f3ade6790db67f80fef60df84424f8964
tree4dc429b6075b3ad2759203617c5c2b9a7277f612
parent82a2e924ff2c6accbc840dfa46c42b24da457a31
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@codeaurora.org
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmalloc.c