4.14-stable review patch. If anyone has any objections, please let me know.
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From: Chintan Pandya cpandya@codeaurora.org
[ 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... 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 --- mm/vmalloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1519,7 +1519,7 @@ 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); @@ -1529,6 +1529,7 @@ 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;