On 08/30, Chao Yu wrote:
On 2022/8/30 5:52, Jaegeuk Kim wrote:
Sometimes we can get a cached meta_inode which has no aops yet. Let's set it all the time to fix the below panic.
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000086000004 EC = 0x21: IABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault user pgtable: 4k pages, 48-bit VAs, pgdp=0000000109ee4000 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 86000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 3045 Comm: syz-executor330 Not tainted 6.0.0-rc2-syzkaller-16455-ga41a877bc12d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : 0x0 lr : folio_mark_dirty+0xbc/0x208 mm/page-writeback.c:2748 sp : ffff800012783970 x29: ffff800012783970 x28: 0000000000000000 x27: ffff800012783b08 x26: 0000000000000001 x25: 0000000000000400 x24: 0000000000000001 x23: ffff0000c736e000 x22: 0000000000000045 x21: 05ffc00000000015 x20: ffff0000ca7403b8 x19: fffffc00032ec600 x18: 0000000000000181 x17: ffff80000c04d6bc x16: ffff80000dbb8658 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: ff808000083e9814 x10: 0000000000000000 x9 : ffff8000083e9814 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : ffff0000cbb19000 x4 : ffff0000cb3d2000 x3 : ffff0000cbb18f80 x2 : fffffffffffffff0 x1 : fffffc00032ec600 x0 : ffff0000ca7403b8 Call trace: 0x0 set_page_dirty+0x38/0xbc mm/folio-compat.c:62 f2fs_update_meta_page+0x80/0xa8 fs/f2fs/segment.c:2369 do_checkpoint+0x794/0xea8 fs/f2fs/checkpoint.c:1522 f2fs_write_checkpoint+0x3b8/0x568 fs/f2fs/checkpoint.c:1679
Cc: stable@vger.kernel.org Reported-by: syzbot+775a3440817f74fddb8c@syzkaller.appspotmail.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org
fs/f2fs/inode.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 6d11c365d7b4..1feb0a8a699e 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -490,10 +490,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) if (!inode) return ERR_PTR(-ENOMEM);
- if (!(inode->i_state & I_NEW)) {
trace_f2fs_iget(inode);return inode;- }
- /* We can see an old cached inode. Let's set the aops all the time. */
Why an old cached inode (has no I_NEW flag) has NULL a_ops pointer? If it is a bad inode, it should be unhashed before unlock_new_inode().
I'm trying to dig further tho, it's not a bad inode, nor I_FREEING | I_CLEAR. It's very werid that thie meta inode is found in newly created superblock by the global hash table. I've checked that the same superblock pointer was used in the previous tests, but inode was evictied all the time.
Thanks,
if (ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi)) goto make_now; @@ -502,6 +499,11 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) goto make_now; #endif
- if (!(inode->i_state & I_NEW)) {
trace_f2fs_iget(inode);return inode;- }
- ret = do_read_inode(inode); if (ret) goto bad_inode;
@@ -557,7 +559,8 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) file_dont_truncate(inode); }
- unlock_new_inode(inode);
- if (inode->i_state & I_NEW)
unlock_new_inode(inode);