diff options
| author | Chintan Pandya <cpandya@codeaurora.org> | 2018-06-07 17:06:50 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-06 16:24:30 +0200 |
| commit | b752dfd91a3e9712aa68468b63725c927adcfaa4 (patch) | |
| tree | 8380937634c4c257d1052a93dba98c6813ceaccb /mm | |
| parent | e6960af9566e9aeee3db07ac2d6a4f70f5731948 (diff) | |
mm: vmalloc: avoid racy handling of debugobjects in vunmap
[ Upstream commit f3c01d2f3ade6790db67f80fef60df84424f8964 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmalloc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 8e3c9c5a3042..de8e372ece04 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1460,7 +1460,7 @@ static void __vunmap(const void *addr, int deallocate_pages) 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); @@ -1470,6 +1470,7 @@ static void __vunmap(const void *addr, int deallocate_pages) 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; |