If GET_SEGNO return NULL_SEGNO for some unecpected case,
update_sit_entry will access invalid memory address,
cause system crash. It is better to do sanity check about
GET_SEGNO just like update_segment_mtime & locate_dirty_segment.

Also remove some redundant judgment code.

Signed-off-by: Zhiguo Niu <zhiguo....@unisoc.com>
---
 fs/f2fs/segment.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index c616e7a..f8a823f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2407,6 +2407,8 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, 
block_t blkaddr, int del)
 #endif
 
        segno = GET_SEGNO(sbi, blkaddr);
+       if (segno == NULL_SEGNO)
+               return;
 
        se = get_seg_entry(sbi, segno);
        new_vblocks = se->valid_blocks + del;
@@ -3504,8 +3506,7 @@ int f2fs_allocate_data_block(struct f2fs_sb_info *sbi, 
struct page *page,
         * since SSR needs latest valid block information.
         */
        update_sit_entry(sbi, *new_blkaddr, 1);
-       if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
-               update_sit_entry(sbi, old_blkaddr, -1);
+       update_sit_entry(sbi, old_blkaddr, -1);
 
        /*
         * If the current segment is full, flush it out and replace it with a
-- 
1.9.1



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