On Wed, Jul 18, 2018 at 1:02 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > On Wed, Jul 18, 2018 at 12:49 PM, Tetsuo Handa > <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: >> Dmitry, >> >> this is yet another example of stalling inside __bread_gfp(). >> >> Can you find all reports where NMI backtrace contains __bread_gfp ? >> >> I need to wget all reports if I try to do that on my side. >> If you can locally grep on your side, it will be nice. > > > No, I don't have grep. But here are some of the matches: > > https://groups.google.com/forum/#!searchin/syzkaller-bugs/__bread_gfp%7Csort:date > https://groups.google.com/forum/#!searchin/syzkaller-upstream-moderation/__bread_gfp%7Csort:date > > > >> On 2018/07/18 19:38, syzbot wrote: >>> CPU: 1 PID: 19991 Comm: syz-executor1 Not tainted 4.18.0-rc5+ #152 >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >>> RIP: 0010:__lock_is_held+0x76/0x140 kernel/locking/lockdep.c:3741 >>> Code: 00 00 4c 8b 6d c8 4d 8d b4 24 38 08 00 00 45 31 ff 48 b8 00 00 00 00 00 fc ff df 49 c1 ed 03 49 01 c5 41 8b 84 24 30 08 00 00 <85> c0 7f 24 e9 85 00 00 00 41 0f b6 45 00 41 83 c7 01 84 c0 74 08 >>> RSP: 0018:ffff88018ea3eed8 EFLAGS: 00000086 >>> RAX: 0000000000000001 RBX: 0000000000000286 RCX: ffffc9000443f000 >>> RDX: 1ffff10031c245de RSI: 00000000ffffffff RDI: ffffffff88f925e0 >>> RBP: ffff88018ea3ef18 R08: ffff88018e1226c0 R09: ffffed003b5e46d6 >>> R10: 0000000000000003 R11: 0000000000000001 R12: ffff88018e1226c0 >>> R13: ffffed0031c245de R14: ffff88018e122ef8 R15: 0000000000000000 >>> FS: 00007f243a415700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: ffffffffff600400 CR3: 00000001d8749000 CR4: 00000000001406e0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> Call Trace: >>> lock_is_held_type+0x121/0x210 kernel/locking/lockdep.c:3962 >>> lock_is_held include/linux/lockdep.h:344 [inline] >>> ___might_sleep+0x295/0x330 kernel/sched/core.c:6152 >>> __might_sleep+0x95/0x190 kernel/sched/core.c:6140 >>> lock_page include/linux/pagemap.h:481 [inline] >>> pagecache_get_page+0x787/0xe40 mm/filemap.c:1554 >>> find_or_create_page include/linux/pagemap.h:322 [inline] >>> grow_dev_page fs/buffer.c:940 [inline] >>> grow_buffers fs/buffer.c:1009 [inline] >>> __getblk_slow fs/buffer.c:1036 [inline] >>> __getblk_gfp+0x3bb/0xb10 fs/buffer.c:1313 >>> __bread_gfp+0x2d/0x310 fs/buffer.c:1347 >>> sb_bread_unmovable include/linux/buffer_head.h:313 [inline] >>> ext4_fill_super+0x6de/0xda80 fs/ext4/super.c:3541 >>> mount_bdev+0x30c/0x3e0 fs/super.c:1174 >>> ext4_mount+0x34/0x40 fs/ext4/super.c:5844 >>> mount_fs+0xae/0x328 fs/super.c:1277 >>> vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 >>> vfs_kern_mount fs/namespace.c:1027 [inline] >>> do_new_mount fs/namespace.c:2518 [inline] >>> do_mount+0x581/0x30e0 fs/namespace.c:2848 >>> ksys_mount+0x12d/0x140 fs/namespace.c:3064 >>> __do_sys_mount fs/namespace.c:3078 [inline] >>> __se_sys_mount fs/namespace.c:3075 [inline] >>> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 >>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >>> entry_SYSCALL_64_after_hwframe+0x49/0xbe This seems to be related to 9p. After rerunning the log I got: root@syzkaller:~# ps afxu | grep syz root 18253 0.0 0.0 0 0 ttyS0 Zl 10:16 0:00 \_ [syz-executor] <defunct> root@syzkaller:~# cat /proc/18253/task/*/stack [<0>] p9_client_rpc+0x3a2/0x1400 [<0>] p9_client_flush+0x134/0x2a0 [<0>] p9_client_rpc+0x122c/0x1400 [<0>] p9_client_create+0xc56/0x16af [<0>] v9fs_session_init+0x21a/0x1a80 [<0>] v9fs_mount+0x7c/0x900 [<0>] mount_fs+0xae/0x328 [<0>] vfs_kern_mount.part.34+0xdc/0x4e0 [<0>] do_mount+0x581/0x30e0 [<0>] ksys_mount+0x12d/0x140 [<0>] __x64_sys_mount+0xbe/0x150 [<0>] do_syscall_64+0x1b9/0x820 [<0>] entry_SYSCALL_64_after_hwframe+0x49/0xbe [<0>] 0xffffffffffffffff There is a bunch of hangs in 9p, so let's do: #syz dup: INFO: task hung in flush_work
