From: Jaewon Kim jaewon31.kim@samsung.com
[ Upstream commit 09ef5283fd96ac424ef0e569626f359bf9ab86c9 ]
On passing requirement to vm_unmapped_area, arch_get_unmapped_area and arch_get_unmapped_area_topdown did not set align_offset. Internally on both unmapped_area and unmapped_area_topdown, if info->align_mask is 0, then info->align_offset was meaningless.
But commit df529cabb7a2 ("mm: mmap: add trace point of vm_unmapped_area") always prints info->align_offset even though it is uninitialized.
Fix this uninitialized value issue by setting it to 0 explicitly.
Before: vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022
After: vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0
Signed-off-by: Jaewon Kim jaewon31.kim@samsung.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Michel Lespinasse walken@google.com Cc: Borislav Petkov bp@suse.de Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/mmap.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/mm/mmap.c b/mm/mmap.c index a3584a90c55c2..ba78f1f1b1bd1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2126,6 +2126,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, info.low_limit = mm->mmap_base; info.high_limit = mmap_end; info.align_mask = 0; + info.align_offset = 0; return vm_unmapped_area(&info); } #endif @@ -2167,6 +2168,7 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, info.low_limit = max(PAGE_SIZE, mmap_min_addr); info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); info.align_mask = 0; + info.align_offset = 0; addr = vm_unmapped_area(&info);
/*