This patch fixes the following KASAN report. The @ioend has been
freed by dio_put(), but the iomap_finish_ioend() still trys to access
its data.
[20563.631624] BUG: KASAN: use-after-free in iomap_finish_ioend+0x58c/0x5c0
[20563.638319] Read of size 8 at addr fffffc0c54a36928 by task kworker/123:2/22184
[20563.647107] CPU: 123 PID: 22184 Comm: kworker/123:2 Not tainted 5.4.0+ #1
[20563.653887] Hardware name: HPE Apollo 70 /C01_APACHE_MB , BIOS L50_5.13_1.11 06/18/2019
[20563.664499] Workqueue: xfs-conv/sda5 xfs_end_io [xfs]
[20563.669547] Call trace:
[20563.671993] dump_backtrace+0x0/0x370
[20563.675648] show_stack+0x1c/0x28
[20563.678958] dump_stack+0x138/0x1b0
[20563.682455] print_address_description.isra.9+0x60/0x378
[20563.687759] __kasan_report+0x1a4/0x2a8
[20563.691587] kasan_report+0xc/0x18
[20563.694985] __asan_report_load8_noabort+0x18/0x20
[20563.699769] iomap_finish_ioend+0x58c/0x5c0
[20563.703944] iomap_finish_ioends+0x110/0x270
[20563.708396] xfs_end_ioend+0x168/0x598 [xfs]
[20563.712823] xfs_end_io+0x1e0/0x2d0 [xfs]
[20563.716834] process_one_work+0x7f0/0x1ac8
[20563.720922] worker_thread+0x334/0xae0
[20563.724664] kthread+0x2c4/0x348
[20563.727889] ret_from_fork+0x10/0x18
[20563.732941] Allocated by task 83403:
[20563.736512] save_stack+0x24/0xb0
[20563.739820] __kasan_kmalloc.isra.9+0xc4/0xe0
[20563.744169] kasan_slab_alloc+0x14/0x20
[20563.747998] slab_post_alloc_hook+0x50/0xa8
[20563.752173] kmem_cache_alloc+0x154/0x330
[20563.756185] mempool_alloc_slab+0x20/0x28
[20563.760186] mempool_alloc+0xf4/0x2a8
[20563.763845] bio_alloc_bioset+0x2d0/0x448
[20563.767849] iomap_writepage_map+0x4b8/0x1740
[20563.772198] iomap_do_writepage+0x200/0x8d0
[20563.776380] write_cache_pages+0x8a4/0xed8
[20563.780469] iomap_writepages+0x4c/0xb0
[20563.784463] xfs_vm_writepages+0xf8/0x148 [xfs]
[20563.788989] do_writepages+0xc8/0x218
[20563.792658] __writeback_single_inode+0x168/0x18f8
[20563.797441] writeback_sb_inodes+0x370/0xd30
[20563.801703] wb_writeback+0x2d4/0x1270
[20563.805446] wb_workfn+0x344/0x1178
[20563.808928] process_one_work+0x7f0/0x1ac8
[20563.813016] worker_thread+0x334/0xae0
[20563.816757] kthread+0x2c4/0x348
[20563.819979] ret_from_fork+0x10/0x18
[20563.825028] Freed by task 22184:
[20563.828251] save_stack+0x24/0xb0
[20563.831559] __kasan_slab_free+0x10c/0x180
[20563.835648] kasan_slab_free+0x10/0x18
[20563.839389] slab_free_freelist_hook+0xb4/0x1c0
[20563.843912] kmem_cache_free+0x8c/0x3e8
[20563.847745] mempool_free_slab+0x20/0x28
[20563.851660] mempool_free+0xd4/0x2f8
[20563.855231] bio_free+0x33c/0x518
[20563.858537] bio_put+0xb8/0x100
[20563.861672] iomap_finish_ioend+0x168/0x5c0
[20563.865847] iomap_finish_ioends+0x110/0x270
[20563.870328] xfs_end_ioend+0x168/0x598 [xfs]
[20563.874751] xfs_end_io+0x1e0/0x2d0 [xfs]
[20563.878755] process_one_work+0x7f0/0x1ac8
[20563.882844] worker_thread+0x334/0xae0
[20563.886584] kthread+0x2c4/0x348
[20563.889804] ret_from_fork+0x10/0x18
[20563.894855] The buggy address belongs to the object at fffffc0c54a36900
which belongs to the cache bio-1 of size 248
[20563.906844] The buggy address is located 40 bytes inside of
248-byte region [fffffc0c54a36900, fffffc0c54a369f8)
[20563.918485] The buggy address belongs to the page:
[20563.923269] page:ffffffff82f528c0 refcount:1 mapcount:0 mapping:fffffc8e4ba31900 index:0xfffffc0c54a33300
[20563.932832] raw: 17ffff8000000200 ffffffffa3060100 0000000700000007 fffffc8e4ba31900
[20563.940567] raw: fffffc0c54a33300 0000000080aa0042 00000001ffffffff 0000000000000000
[20563.948300] page dumped because: kasan: bad access detected
[20563.955345] Memory state around the buggy address:
[20563.960129] fffffc0c54a36800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
[20563.967342] fffffc0c54a36880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[20563.974554] >fffffc0c54a36900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[20563.981766] ^
[20563.986288] fffffc0c54a36980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
[20563.993501] fffffc0c54a36a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[20564.000713] ==================================================================
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205703
Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx>
---
Hi,
I can't reproduce this bug by running generic/461 on this patch. But then
generic/461 started to hit below issue:
https://bugzilla.kernel.org/show_bug.cgi?id=205465#c3
Which I reported one month ago. At least it's not a regression from this patch.
Thanks,
Zorro
fs/iomap/buffered-io.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index d33c7bc5ee92..dc25a2183ba9 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1128,6 +1128,7 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error)
struct bio *bio = &ioend->io_inline_bio;
struct bio *last = ioend->io_bio, *next;
u64 start = bio->bi_iter.bi_sector;
+ loff_t offset = ioend->io_offset;
bool quiet = bio_flagged(bio, BIO_QUIET);
for (bio = &ioend->io_inline_bio; bio; bio = next) {
@@ -1148,12 +1149,12 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error)
iomap_finish_page_writeback(inode, bv->bv_page, error);
bio_put(bio);
}
+ /* The ioend has been freed by bio_put() */
if (unlikely(error && !quiet)) {
printk_ratelimited(KERN_ERR
"%s: writeback error on inode %lu, offset %lld, sector %llu",
- inode->i_sb->s_id, inode->i_ino, ioend->io_offset,
- start);
+ inode->i_sb->s_id, inode->i_ino, offset, start);
}
}
--
2.20.1
