The quilt patch titled Subject: squashfs: fix null-ptr-deref in squashfs_fill_super has been removed from the -mm tree. Its filename was squashfs-fix-null-ptr-deref-in-squashfs_fill_super.patch This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Baokun Li <libaokun1@xxxxxxxxxx> Subject: squashfs: fix null-ptr-deref in squashfs_fill_super Date: Tue, 1 Nov 2022 15:33:43 +0800 When squashfs_read_table() returns an error or `sb->s_magic != SQUASHFS_MAGIC`, enters the error branch and calls msblk->thread_ops->destroy(msblk) to destroy msblk. However, msblk->thread_ops has not been initialized. Therefore, the following problem is triggered: ================================================================== BUG: KASAN: null-ptr-deref in squashfs_fill_super+0xe7a/0x13b0 Read of size 8 at addr 0000000000000008 by task swapper/0/1 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc3-next-20221031 #367 Call Trace: <TASK> dump_stack_lvl+0x73/0x9f print_report+0x743/0x759 kasan_report+0xc0/0x120 __asan_load8+0xd3/0x140 squashfs_fill_super+0xe7a/0x13b0 get_tree_bdev+0x27b/0x450 squashfs_get_tree+0x19/0x30 vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 init_mount+0xad/0x100 do_mount_root+0xbc/0x1d0 mount_block_root+0x173/0x316 mount_root+0x223/0x236 prepare_namespace+0x1eb/0x237 kernel_init_freeable+0x528/0x576 kernel_init+0x29/0x250 ret_from_fork+0x1f/0x30 </TASK> ================================================================== To solve this issue, msblk->thread_ops is initialized immediately after msblk is assigned a value. Link: https://lkml.kernel.org/r/20221101073343.3961562-1-libaokun1@xxxxxxxxxx Fixes: b0645770d3c7 ("squashfs: add the mount parameter theads=<single|multi|percpu>") Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx> Reviewed-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx> Reviewed-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx> Cc: Yu Kuai <yukuai3@xxxxxxxxxx> Cc: Zhang Yi <yi.zhang@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/squashfs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/squashfs/super.c~squashfs-fix-null-ptr-deref-in-squashfs_fill_super +++ a/fs/squashfs/super.c @@ -197,6 +197,7 @@ static int squashfs_fill_super(struct su return -ENOMEM; } msblk = sb->s_fs_info; + msblk->thread_ops = opts->thread_ops; msblk->panic_on_errors = (opts->errors == Opt_errors_panic); @@ -231,7 +232,7 @@ static int squashfs_fill_super(struct su sb->s_bdev); goto failed_mount; } - msblk->thread_ops = opts->thread_ops; + if (opts->thread_num == 0) { msblk->max_thread_num = msblk->thread_ops->max_decompressors(); } else { _ Patches currently in -mm which might be from libaokun1@xxxxxxxxxx are