No upstream commit exists for this commit.
Using an arbitrary value that does not fall into the required range as an argument of the shift operator when outputting an error is wrong in itself.
Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_shift_out_of_bounds+0x3bf/0x420 lib/ubsan.c:321 parse_options+0x4ad6/0x4ae0 fs/f2fs/super.c:919 f2fs_fill_super+0x321b/0x7c40 fs/f2fs/super.c:4214 mount_bdev+0x2c9/0x3f0 fs/super.c:1443 legacy_get_tree+0xeb/0x180 fs/fs_context.c:632 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x2ba/0xb40 fs/namespace.c:3051 do_mount fs/namespace.c:3394 [inline] __do_sys_mount fs/namespace.c:3602 [inline] __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3579 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2
There is a commit 87161a2b0aed ("f2fs: deprecate io_bits") that completely removes these strings, but it's not practical to backport it.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Link: syzbot+410500002694f3ff65b1@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=410500002694f3ff65b1 Fixes: ec91538dccd4 ("f2fs: get io size bit from mount option") Signed-off-by: Denis Arefev arefev@swemel.ru --- fs/f2fs/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 72160b906f4b..7d7766761fe4 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -916,8 +916,8 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount) if (args->from && match_int(args, &arg)) return -EINVAL; if (arg <= 0 || arg > __ilog2_u32(BIO_MAX_VECS)) { - f2fs_warn(sbi, "Not support %ld, larger than %d", - BIT(arg), BIO_MAX_VECS); + f2fs_warn(sbi, "Not support 2^%d, invalid argument %d", + arg, BIO_MAX_VECS); return -EINVAL; } F2FS_OPTION(sbi).write_io_size_bits = arg;