On Thu, Jul 02, 2020 at 03:02:14AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: d37d5704 Add linux-next specific files for 20200702 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1549d0a3100000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a0a0972a399422ff > dashboard link: https://syzkaller.appspot.com/bug?extid=bf04628c1f6179269b0b > compiler: gcc (GCC) 10.1.0-syz 20200507 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+bf04628c1f6179269b0b@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: stack-out-of-bounds in bio_list_empty include/linux/bio.h:561 [inline] > BUG: KASAN: stack-out-of-bounds in bio_alloc_bioset+0x5b2/0x5d0 block/bio.c:482 > Read of size 8 at addr ffffc90000fc7150 by task kworker/u4:4/169 I can also reproduce this. It needs to revert 3 commits, https://lore.kernel.org/lkml/20200702141001.GA3834@xxxxxx/ > > CPU: 0 PID: 169 Comm: kworker/u4:4 Not tainted 5.8.0-rc3-next-20200702-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Workqueue: writeback wb_workfn (flush-8:0) > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x18f/0x20d lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383 > __kasan_report mm/kasan/report.c:513 [inline] > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 > bio_list_empty include/linux/bio.h:561 [inline] > bio_alloc_bioset+0x5b2/0x5d0 block/bio.c:482 > bio_clone_fast+0x21/0x1b0 block/bio.c:710 > bio_split+0xc7/0x2c0 block/bio.c:1477 > blk_bio_segment_split block/blk-merge.c:281 [inline] > __blk_queue_split+0x10e2/0x1650 block/blk-merge.c:331 > blk_mq_submit_bio+0x1b0/0x1760 block/blk-mq.c:2169 > __submit_bio_noacct_mq block/blk-core.c:1181 [inline] > submit_bio_noacct+0xc9e/0x12d0 block/blk-core.c:1214 > submit_bio+0x263/0x5b0 block/blk-core.c:1284 > ext4_io_submit fs/ext4/page-io.c:382 [inline] > io_submit_add_bh fs/ext4/page-io.c:423 [inline] > ext4_bio_write_page+0x9a8/0x1c27 fs/ext4/page-io.c:550 > mpage_submit_page+0x140/0x2c0 fs/ext4/inode.c:2082 > mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline] > mpage_map_and_submit_extent fs/ext4/inode.c:2469 [inline] > ext4_writepages+0x237e/0x3960 fs/ext4/inode.c:2782 > do_writepages+0xec/0x290 mm/page-writeback.c:2352 > __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461 > writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721 > __writeback_inodes_wb+0xc6/0x280 fs/fs-writeback.c:1790 > wb_writeback+0x8bb/0xd40 fs/fs-writeback.c:1896 > wb_check_background_flush fs/fs-writeback.c:1964 [inline] > wb_do_writeback fs/fs-writeback.c:2052 [inline] > wb_workfn+0xb20/0x13e0 fs/fs-writeback.c:2080 > process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 > worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 > kthread+0x3b5/0x4a0 kernel/kthread.c:292 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > > addr ffffc90000fc7150 is located in stack of task kworker/u4:4/169 at offset 80 in frame: > arch_atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline] > arch_atomic64_fetch_add_unless include/linux/atomic-arch-fallback.h:2195 [inline] > arch_atomic64_add_unless include/linux/atomic-arch-fallback.h:2220 [inline] > arch_atomic64_inc_not_zero include/linux/atomic-arch-fallback.h:2236 [inline] > atomic64_inc_not_zero include/asm-generic/atomic-instrumented.h:1609 [inline] > atomic_long_inc_not_zero include/asm-generic/atomic-long.h:497 [inline] > percpu_ref_tryget_live include/linux/percpu-refcount.h:282 [inline] > submit_bio_noacct+0x0/0x12d0 block/blk-core.c:433 > > this frame has 3 objects: > [32, 40) 'bio' > [64, 80) 'bio_list' > [96, 128) 'bio_list_on_stack' > > Memory state around the buggy address: > ffffc90000fc7000: 00 00 00 f2 f2 f2 00 00 00 00 00 f3 f3 f3 f3 f3 > ffffc90000fc7080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >ffffc90000fc7100: f1 f1 f1 f1 00 f2 f2 f2 00 00 f2 f2 00 00 00 00 > ^ > ffffc90000fc7180: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > ffffc90000fc7200: 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 00 00 00 00 f3 > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
