This is a note to let you know that I've just added the patch titled
ext2: Use kvmalloc() for group descriptor array
to the 5.15-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:
ext2-use-kvmalloc-for-group-descriptor-array.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b7f079a9dddec99d297c48e9524239a1d4a0b737
Author: Jan Kara <jack@xxxxxxx>
Date: Wed Sep 14 17:29:33 2022 +0200
ext2: Use kvmalloc() for group descriptor array
[ Upstream commit e7c7fbb9a8574ebd89cc05db49d806c7476863ad ]
Array of group descriptor block buffers can get rather large. In theory
in can reach 1MB for perfectly valid filesystem and even more for
maliciously crafted ones. Use kvmalloc() to allocate the array to avoid
straining memory allocator with large order allocations unnecessarily.
Reported-by: syzbot+0f2f7e65a3007d39539f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index fd855574ef09..02d82f8fe85d 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -163,7 +163,7 @@ static void ext2_put_super (struct super_block * sb)
db_count = sbi->s_gdb_count;
for (i = 0; i < db_count; i++)
brelse(sbi->s_group_desc[i]);
- kfree(sbi->s_group_desc);
+ kvfree(sbi->s_group_desc);
kfree(sbi->s_debts);
percpu_counter_destroy(&sbi->s_freeblocks_counter);
percpu_counter_destroy(&sbi->s_freeinodes_counter);
@@ -1080,7 +1080,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
}
db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
EXT2_DESC_PER_BLOCK(sb);
- sbi->s_group_desc = kmalloc_array(db_count,
+ sbi->s_group_desc = kvmalloc_array(db_count,
sizeof(struct buffer_head *),
GFP_KERNEL);
if (sbi->s_group_desc == NULL) {
@@ -1206,7 +1206,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
for (i = 0; i < db_count; i++)
brelse(sbi->s_group_desc[i]);
failed_mount_group_desc:
- kfree(sbi->s_group_desc);
+ kvfree(sbi->s_group_desc);
kfree(sbi->s_debts);
failed_mount:
brelse(bh);
