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| author | Chao Yu <chao@kernel.org> | 2022-12-30 23:43:32 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2023-01-03 08:58:47 -0800 |
| commit | b3d83066cbebc76dbac8a5fca931f64b4c6fff34 (patch) | |
| tree | 57451fcc1f4c9ffa446fb46a7916a406f615f708 | |
| parent | 69b41ac87e4a664de78a395ff97166f0b2943210 (diff) | |
| download | linux-b3d83066cbebc76dbac8a5fca931f64b4c6fff34.tar.gz | |
f2fs: fix to avoid NULL pointer dereference in f2fs_issue_flush()
With below two cases, it will cause NULL pointer dereference when
accessing SM_I(sbi)->fcc_info in f2fs_issue_flush().
a) If kthread_run() fails in f2fs_create_flush_cmd_control(), it will
release SM_I(sbi)->fcc_info,
- mount -o noflush_merge /dev/vda /mnt/f2fs
- mount -o remount,flush_merge /dev/vda /mnt/f2fs -- kthread_run() fails
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync
b) we will never allocate memory for SM_I(sbi)->fcc_info w/ below
testcase,
- mount -o ro /dev/vda /mnt/f2fs
- mount -o rw,remount /dev/vda /mnt/f2fs
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync
In order to fix this issue, let change as below:
- fix error path handling in f2fs_create_flush_cmd_control().
- allocate SM_I(sbi)->fcc_info even if readonly is on.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
| -rw-r--r-- | fs/f2fs/segment.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 25ddea478fc1a8..c3f8c8208eecaa 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -663,8 +663,7 @@ init_thread: if (IS_ERR(fcc->f2fs_issue_flush)) { int err = PTR_ERR(fcc->f2fs_issue_flush); - kfree(fcc); - SM_I(sbi)->fcc_info = NULL; + fcc->f2fs_issue_flush = NULL; return err; } @@ -5138,11 +5137,9 @@ int f2fs_build_segment_manager(struct f2fs_sb_info *sbi) init_f2fs_rwsem(&sm_info->curseg_lock); - if (!f2fs_readonly(sbi->sb)) { - err = f2fs_create_flush_cmd_control(sbi); - if (err) - return err; - } + err = f2fs_create_flush_cmd_control(sbi); + if (err) + return err; err = create_discard_cmd_control(sbi); if (err) |