On Mon, 24 Apr 2023 at 09:21, syzbot <syzbot+da80e6a47db00f8be22c@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 148341f0a2f5 Merge tag 'vfs.misc.fixes.v6.3-rc6' of git://.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=11a5970dc80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=54d63ee086ae78d0 > dashboard link: https://syzkaller.appspot.com/bug?extid=da80e6a47db00f8be22c > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/1c557f92a6e1/disk-148341f0.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/f2c85210e1ce/vmlinux-148341f0.xz > kernel image: https://storage.googleapis.com/syzbot-assets/b019d0447709/bzImage-148341f0.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+da80e6a47db00f8be22c@xxxxxxxxxxxxxxxxxxxxxxxxx I did not fully grasp what happens here, but it looks fishy. The comment on top of blk_add_timer() says "Notes: Each request has its own timer". It looks like it's not true (?). A simple timer can't ensure proper timeout for 2+ commands, right? > ================================================================== > BUG: KCSAN: data-race in __mod_timer / blk_add_timer > > write to 0xffff88810285dd20 of 8 bytes by task 26833 on cpu 0: > __mod_timer+0x625/0x890 kernel/time/timer.c:1121 > mod_timer+0x1f/0x30 kernel/time/timer.c:1190 > blk_add_timer+0x184/0x190 block/blk-timeout.c:164 > blk_mq_start_request+0x100/0x2b0 block/blk-mq.c:1264 > scsi_queue_rq+0x143b/0x1990 drivers/scsi/scsi_lib.c:1756 > blk_mq_dispatch_rq_list+0x7b1/0x11f0 block/blk-mq.c:2059 > __blk_mq_do_dispatch_sched block/blk-mq-sched.c:172 [inline] > blk_mq_do_dispatch_sched+0x4de/0x820 block/blk-mq-sched.c:186 > __blk_mq_sched_dispatch_requests+0x1c1/0x260 > blk_mq_sched_dispatch_requests+0x93/0x100 block/blk-mq-sched.c:338 > __blk_mq_run_hw_queue+0x8e/0x110 block/blk-mq.c:2177 > __blk_mq_delay_run_hw_queue+0xb3/0x3a0 block/blk-mq.c:2253 > blk_mq_run_hw_queue+0x19f/0x330 block/blk-mq.c:2301 > blk_mq_sched_insert_requests+0x1da/0x2c0 block/blk-mq-sched.c:492 > blk_mq_dispatch_plug_list block/blk-mq.c:2748 [inline] > blk_mq_flush_plug_list+0x519/0x660 block/blk-mq.c:2790 > __blk_flush_plug+0x223/0x280 block/blk-core.c:1153 > blk_finish_plug+0x47/0x60 block/blk-core.c:1177 > ext4_do_writepages+0x1c08/0x2140 fs/ext4/inode.c:2927 > ext4_writepages+0x127/0x250 fs/ext4/inode.c:2964 > do_writepages+0x1c5/0x340 mm/page-writeback.c:2551 > filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:390 > __filemap_fdatawrite_range mm/filemap.c:423 [inline] > file_write_and_wait_range+0xfa/0x190 mm/filemap.c:781 > ext4_sync_file+0x10d/0x720 fs/ext4/fsync.c:151 > vfs_fsync_range+0x10b/0x120 fs/sync.c:188 > generic_write_sync include/linux/fs.h:2452 [inline] > ext4_buffered_write_iter+0x397/0x3e0 fs/ext4/file.c:296 > ext4_file_write_iter+0xd7/0x10e0 > do_iter_write+0x418/0x700 fs/read_write.c:861 > vfs_iter_write+0x50/0x70 fs/read_write.c:902 > iter_file_splice_write+0x456/0x7d0 fs/splice.c:778 > do_splice_from fs/splice.c:856 [inline] > direct_splice_actor+0x84/0xa0 fs/splice.c:1022 > splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:977 > do_splice_direct+0x104/0x180 fs/splice.c:1065 > do_sendfile+0x3b8/0x950 fs/read_write.c:1255 > __do_sys_sendfile64 fs/read_write.c:1317 [inline] > __se_sys_sendfile64 fs/read_write.c:1309 [inline] > __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1309 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > read to 0xffff88810285dd20 of 8 bytes by task 2708 on cpu 1: > blk_add_timer+0x118/0x190 > blk_mq_start_request+0x100/0x2b0 block/blk-mq.c:1264 > scsi_queue_rq+0x143b/0x1990 drivers/scsi/scsi_lib.c:1756 > blk_mq_dispatch_rq_list+0x7b1/0x11f0 block/blk-mq.c:2059 > __blk_mq_do_dispatch_sched block/blk-mq-sched.c:172 [inline] > blk_mq_do_dispatch_sched+0x4de/0x820 block/blk-mq-sched.c:186 > __blk_mq_sched_dispatch_requests+0x1c1/0x260 > blk_mq_sched_dispatch_requests+0x93/0x100 block/blk-mq-sched.c:338 > __blk_mq_run_hw_queue+0x8e/0x110 block/blk-mq.c:2177 > __blk_mq_delay_run_hw_queue+0xb3/0x3a0 block/blk-mq.c:2253 > blk_mq_run_hw_queue+0x19f/0x330 block/blk-mq.c:2301 > blk_mq_sched_insert_requests+0x1da/0x2c0 block/blk-mq-sched.c:492 > blk_mq_dispatch_plug_list block/blk-mq.c:2748 [inline] > blk_mq_flush_plug_list+0x519/0x660 block/blk-mq.c:2790 > __blk_flush_plug+0x223/0x280 block/blk-core.c:1153 > blk_finish_plug+0x47/0x60 block/blk-core.c:1177 > jbd2_journal_commit_transaction+0x1c09/0x33f0 fs/jbd2/commit.c:797 > kjournald2+0x242/0x420 fs/jbd2/journal.c:209 > kthread+0x1ac/0x1e0 kernel/kthread.c:376 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 > > value changed: 0x0000000100014674 -> 0x00000001000148f4 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 2708 Comm: jbd2/sda1-8 Not tainted 6.3.0-rc5-syzkaller-00005-g148341f0a2f5 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 > ================================================================== > > > --- > This report 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 issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000ff17f705fa0fdbd7%40google.com.
