| Message ID | tencent_10694B411BC625A4BA1BBB8033959EA31B08@qq.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ocfs2: BUG is meaningless when the flags is 0 | expand |
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c index f7672472fa82..0043c2428ef2 100644 --- a/fs/ocfs2/extent_map.c +++ b/fs/ocfs2/extent_map.c @@ -968,7 +968,8 @@ int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr, if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >= i_size_read(inode)) { - BUG_ON(!(flags & OCFS2_BH_READAHEAD)); + BUG_ON(flags && !(flags & OCFS2_BH_READAHEAD)); + rc = flags ?: -EIO; goto out; }
Syzbot reported a BUG in ocfs2_read_virt_blocks. ------------[ cut here ]------------ kernel BUG at fs/ocfs2/extent_map.c:971! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 UID: 0 PID: 5221 Comm: syz-executor117 Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:ocfs2_read_virt_blocks+0xaa3/0xb20 fs/ocfs2/extent_map.c:971 Code: 8b 54 24 30 8b 4c 24 1c 4c 8b 44 24 38 45 89 e1 ff 74 24 48 e8 7e 0a 0c 00 48 83 c4 08 eb 25 e8 43 d2 34 08 e8 ee d1 0c fe 90 <0f> 0b e8 e6 d1 0c fe 4c 89 e8 45 89 e5 49 89 c4 e9 01 f7 ff ff e8 RSP: 0018:ffffc90002e2e820 EFLAGS: 00010293 RAX: ffffffff83881432 RBX: 0000000000000000 RCX: ffff88802d3e9e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90002e2e9f0 R08: ffffffff83880eae R09: 1ffffffff203781d R10: dffffc0000000000 R11: fffffbfff203781e R12: ffff8880764d8878 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff920005c5d18 FS: 000055557cd55380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005628fd41e058 CR3: 000000002d2e6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ocfs2_read_dir_block+0x106/0x5c0 fs/ocfs2/dir.c:508 ocfs2_find_dir_space_el fs/ocfs2/dir.c:3427 [inline] // status = ocfs2_read_dir_block(dir, 0, &bh, 0); ocfs2_prepare_dir_for_insert+0x3f2/0x5c60 fs/ocfs2/dir.c:4274 ocfs2_mknod+0xcaf/0x2b40 fs/ocfs2/namei.c:292 ocfs2_create+0x1ab/0x480 fs/ocfs2/namei.c:672 lookup_open fs/namei.c:3595 [inline] open_last_lookups fs/namei.c:3694 [inline] path_openat+0x1c03/0x3590 fs/namei.c:3930 do_filp_open+0x235/0x490 fs/namei.c:3960 do_sys_openat2+0x13e/0x1d0 fs/open.c:1415 do_sys_open fs/open.c:1430 [inline] __do_sys_openat fs/open.c:1446 [inline] __se_sys_openat fs/open.c:1441 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1441 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f It is because the parameter v_block passed to ocfs2_read_virt_blocks() is 0, nr is 1, and inode->i_size is 0, and flags are also 0. In this path, v_block, flags, and nr are fixed values that are hard coded, so if i_size is 0, the bug will be triggered. Therefore, it is more meaningful to check if the flags contain the READHEAD bit when their value is non-zero. Reported-and-tested-by: syzbot+797d4829dafe3f11dce7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=797d4829dafe3f11dce7 Signed-off-by: Edward Adam Davis <eadavis@qq.com> --- fs/ocfs2/extent_map.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)