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ANDROID: mm: page_pinner: use put_user_page at seq_print_vma_name

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seq_print_vma_name uses get_user_pages_remote so it should
use put_user_page to close false positive of page_pinner.

Page pinned via pid 930, ts 38241618218 ns
PFN 10351665 Block 10109 type CMA Flags 0x8000000000080034(uptodate|lru|active|swapbacked)
 __set_page_pinner+0x34/0xb4
 try_grab_page+0x18c/0x1a0
 follow_page_pte+0x2b4/0x4a8
 follow_pmd_mask+0x180/0x4a4
 __get_user_pages+0x1a0/0x434
 __get_user_pages_remote+0xa4/0x28c
 get_user_pages_remote+0x20/0x48
 seq_print_vma_name+0xa4/0x1f4
 show_smap+0x114/0x25c
 seq_read_iter+0x2e8/0x3e8
 seq_read+0xec/0x124
 vfs_read+0xe0/0x2dc
 ksys_read+0x7c/0xec
 __arm64_sys_read+0x20/0x30
 el0_svc_common+0xa4/0x180
 do_el0_svc+0x28/0x88

Bug: 183414571
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Minchan Kim <minchan@google.com>
Change-Id: Ib81ccbc486877aab5e561ef516cedcbb172736f1
This commit is contained in:
Minchan Kim 2021-03-18 13:44:59 -07:00 • committed by Minchan Kim
commit d14850835c
1 changed files with 1 additions and 1 deletions
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2
fs/proc/task_mmu.c
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@ -159,7 +159,7 @@ static void seq_print_vma_name(struct seq_file *m, struct vm_area_struct *vma)
write_len = strnlen(kaddr + page_offset, len);
seq_write(m, kaddr + page_offset, write_len);
kunmap(page);
put_page(page);
put_user_page(page);
/* if strnlen hit a null terminator then we're done */
if (write_len != len)