On 2019/11/26 下午4:17, Qu Wenruo wrote: > Hi guys, > > Just got a reproducible error in btrfs/058. > The backtrace is completely in VFS territory, not btrfs related lock at all: With the help of Nikolay and Johannes, the offending commit is pinned down to 0be0ee71816b ("vfs: properly and reliably lock f_pos in fdget_pos()"), and Linus will soon revert it. Not a big deal, but testers would have a much easier life using David's misc-5.5 (still based on v5.4-rc). And to David, would you please keep your misc-5.5 branch until the offending patch get reverted? Thanks, Qu > BTRFS info (device dm-5): checking UUID tree > sysrq: Show Blocked State > task PC stack pid father > rm D 0 560678 560445 0x00000000 > Call Trace: > __schedule+0x5c7/0xea0 > ? __sched_text_start+0x8/0x8 > ? lock_downgrade+0x380/0x380 > ? lock_contended+0x730/0x730 > ? debug_check_no_locks_held+0x60/0x60 > schedule+0x7b/0x170 > schedule_preempt_disabled+0x18/0x30 > __mutex_lock+0x481/0xc70 > ? __fdget_pos+0x7e/0x80 > ? mutex_trylock+0x190/0x190 > ? debug_lockdep_rcu_enabled+0x26/0x40 > ? kmem_cache_free+0x157/0x3b0 > ? putname+0x73/0x80 > ? __ia32_sys_rmdir+0x30/0x30 > ? __check_object_size+0x134/0x1e6 > mutex_lock_nested+0x1b/0x20 > ? mutex_lock_nested+0x1b/0x20 > __fdget_pos+0x7e/0x80 > ksys_lseek+0x1d/0xf0 > __x64_sys_lseek+0x43/0x50 > do_syscall_64+0x79/0xe0 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x7f7518e5652b > Code: Bad RIP value. > RSP: 002b:00007ffead7508e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7518e5652b > RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 00007f7518f267e0 R08: 0000000000000001 R09: 0000000000000001 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000002 R14: 00007f7518f2be68 R15: 00007f7518f287e0 > > Is this a known bug in VFS layer? > > Thanks, > Qu >
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