mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-19 23:26:49 +07:00
7df1c170b9
The node directory lookup code uses a state structure that tracks the path of buffers used to search for the hash of a filename through the leaf blocks. When the lookup encounters a block that ends with the requested hash, but the entry has not yet been found, it must shift over to the next block and continue looking for the entry (i.e., duplicate hashes could continue over into the next block). This shift mechanism involves walking back up and down the state structure, replacing buffers at the appropriate btree levels as necessary. When a buffer is replaced, the old buffer is released and the new buffer read into the active slot in the path structure. Because the buffer is read directly into the path slot, a buffer read failure can result in setting a NULL buffer pointer in an active slot. This throws off the state cleanup code in xfs_dir2_node_lookup(), which expects to release a buffer from each active slot. Instead, a BUG occurs due to a NULL pointer dereference: BUG: unable to handle kernel NULL pointer dereference at 00000000000001e8 IP: [<ffffffffa0585063>] xfs_trans_brelse+0x2a3/0x3c0 [xfs] ... RIP: 0010:[<ffffffffa0585063>] [<ffffffffa0585063>] xfs_trans_brelse+0x2a3/0x3c0 [xfs] ... Call Trace: [<ffffffffa05250c6>] xfs_dir2_node_lookup+0xa6/0x2c0 [xfs] [<ffffffffa0519f7c>] xfs_dir_lookup+0x1ac/0x1c0 [xfs] [<ffffffffa055d0e1>] xfs_lookup+0x91/0x290 [xfs] [<ffffffffa05580b3>] xfs_vn_lookup+0x73/0xb0 [xfs] [<ffffffff8122de8d>] lookup_real+0x1d/0x50 [<ffffffff8123330e>] path_openat+0x91e/0x1490 [<ffffffff81235079>] do_filp_open+0x89/0x100 ... This has been reproduced via a parallel fsstress and filesystem shutdown workload in a loop. The shutdown triggers the read error in the aforementioned codepath and causes the BUG in xfs_dir2_node_lookup(). Update xfs_da3_path_shift() to update the active path slot atomically with respect to the caller when a buffer is replaced. This ensures that the caller always sees the old or new buffer in the slot and prevents the NULL pointer dereference. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> |
||
|---|---|---|
| .. | ||
| xfs_alloc_btree.c | ||
| xfs_alloc_btree.h | ||
| xfs_alloc.c | ||
| xfs_alloc.h | ||
| xfs_attr_leaf.c | ||
| xfs_attr_leaf.h | ||
| xfs_attr_remote.c | ||
| xfs_attr_remote.h | ||
| xfs_attr_sf.h | ||
| xfs_attr.c | ||
| xfs_bit.h | ||
| xfs_bmap_btree.c | ||
| xfs_bmap_btree.h | ||
| xfs_bmap.c | ||
| xfs_bmap.h | ||
| xfs_btree.c | ||
| xfs_btree.h | ||
| xfs_cksum.h | ||
| xfs_da_btree.c | ||
| xfs_da_btree.h | ||
| xfs_da_format.c | ||
| xfs_da_format.h | ||
| xfs_dir2_block.c | ||
| xfs_dir2_data.c | ||
| xfs_dir2_leaf.c | ||
| xfs_dir2_node.c | ||
| xfs_dir2_priv.h | ||
| xfs_dir2_sf.c | ||
| xfs_dir2.c | ||
| xfs_dir2.h | ||
| xfs_dquot_buf.c | ||
| xfs_format.h | ||
| xfs_fs.h | ||
| xfs_ialloc_btree.c | ||
| xfs_ialloc_btree.h | ||
| xfs_ialloc.c | ||
| xfs_ialloc.h | ||
| xfs_inode_buf.c | ||
| xfs_inode_buf.h | ||
| xfs_inode_fork.c | ||
| xfs_inode_fork.h | ||
| xfs_log_format.h | ||
| xfs_log_recover.h | ||
| xfs_log_rlimit.c | ||
| xfs_quota_defs.h | ||
| xfs_rtbitmap.c | ||
| xfs_sb.c | ||
| xfs_sb.h | ||
| xfs_shared.h | ||
| xfs_symlink_remote.c | ||
| xfs_trans_resv.c | ||
| xfs_trans_resv.h | ||
| xfs_trans_space.h | ||
| xfs_types.h | ||