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Commit 3993b112 authored by Colin Ian King's avatar Colin Ian King Committed by David Sterba
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btrfs: avoid null pointer dereference on fs_info when calling btrfs_crit 



There are checks on fs_info in __btrfs_panic to avoid dereferencing a
null fs_info, however, there is a call to btrfs_crit that may also
dereference a null fs_info. Fix this by adding a check to see if fs_info
is null and only print the s_id if fs_info is non-null.

Detected by CoverityScan CID#401973 ("Dereference after null check")

Fixes: efe120a0 ("Btrfs: convert printk to btrfs_ and fix BTRFS prefix")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent fa0d0888

fs/btrfs/super.c

+2 −2
Original line number Diff line number Diff line
@@ -202,7 +202,6 @@ static struct ratelimit_state printk_limits[] = { 


void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)

{

	struct super_block *sb = fs_info->sb;

	char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";

	struct va_format vaf;

	va_list args;
@@ -228,7 +227,8 @@ void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...) 
	vaf.va = &args;



	if (__ratelimit(ratelimit))

		printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);

		printk("%sBTRFS %s (device %s): %pV\n", lvl, type,

			fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);



	va_end(args);

}