On Thu, Dec 05, 2019 at 02:51:32PM +0800, Zorro Lang wrote: > 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> Pretty clearly a scrwup on my part. Fixes: 9cd0ed63ca514 ("iomap: enhance writeback error message") Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --D > --- > > 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 >
