This is a note to let you know that I've just added the patch titled
ext4: don't try to processed freed blocks until mballoc is initialized
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-don-t-try-to-processed-freed-blocks-until-mball.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 144c3aa759dd8a4d633f4533eeb628ac08696ce6
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Thu Jan 21 12:33:20 2021 -0500
ext4: don't try to processed freed blocks until mballoc is initialized
[ Upstream commit 027f14f5357279655c3ebc6d14daff8368d4f53f ]
If we try to make any changes via the journal between when the journal
is initialized, but before the multi-block allocated is initialized,
we will end up deferencing a NULL pointer when the journal commit
callback function calls ext4_process_freed_data().
The proximate cause of this failure was commit 2d01ddc86606 ("ext4:
save error info to sb through journal if available") since file system
corruption problems detected before the call to ext4_mb_init() would
result in a journal commit before we aborted the mount of the file
system.... and we would then trigger the NULL pointer deref.
Link: https://lore.kernel.org/r/YAm8qH/0oo2ofSMR@xxxxxxx
Reported-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9a6f9875aa34..2ae0af1c88c7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4875,7 +4875,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
- sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
sbi->s_journal->j_submit_inode_data_buffers =
ext4_journal_submit_inode_data_buffers;
sbi->s_journal->j_finish_inode_data_buffers =
@@ -4987,6 +4986,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount5;
}
+ /*
+ * We can only set up the journal commit callback once
+ * mballoc is initialized
+ */
+ if (sbi->s_journal)
+ sbi->s_journal->j_commit_callback =
+ ext4_journal_commit_callback;
+
block = ext4_count_free_clusters(sb);
ext4_free_blocks_count_set(sbi->s_es,
EXT4_C2B(sbi, block));
