Re: crash zfs_clone_range()

From: Ronald Klop <ronald-lists_at_klop.ws>
Date: Tue, 14 Nov 2023 15:21:45 UTC
Van: Ronald Klop <ronald-lists@klop.ws>
Datum: dinsdag, 14 november 2023 13:59
Aan: Konstantin Belousov <kostikbel@gmail.com>
CC: Alexander Motin <mav@freebsd.org>, current@freebsd.org
Onderwerp: Re: crash zfs_clone_range()
> 
> Response below
>  
> Van: Konstantin Belousov <kostikbel@gmail.com>
> Datum: zondag, 12 november 2023 19:47
> Aan: Alexander Motin <mav@freebsd.org>
> CC: Ronald Klop <ronald-lists@klop.ws>, current@freebsd.org
> Onderwerp: Re: crash zfs_clone_range()
>> 
>> On Sun, Nov 12, 2023 at 11:51:40AM -0500, Alexander Motin wrote:
>> > Hi Ronald,
>> >
>> > As I can see, the clone request to ZFS came through nullfs, and it crashed
>> > immediately on enter.  I've never been a VFS layer expert, but to me it may
>> > be a nullfs problem, not zfs.  Is there chance you was (un-)mounting
>> > something when this happened?
>> It is not nullfs issue, I believe, but the lack of the busy reference on the
>> upper mount.  I think https://reviews.freebsd.org/D42554 should cover it.
>> 
>> >
>> > On 10.11.2023 05:12, Ronald Klop wrote:
>> > > Hi,
>> > >
>> > > Had this crash today on RPI4/15-CURRENT.
>> > >
>> > > FreeBSD rpi4 15.0-CURRENT FreeBSD 15.0-CURRENT #19
>> > > main-b0203aaa46-dirty: Sat Nov  4 11:48:33 CET 2023     ronald@rpi4:/home/ronald/dev/freebsd/obj/home/ronald/dev/freebsd/src/arm64.aarch64/sys/GENERIC-NODEBUG
>> > > arm64
>> > >
>> > > $ sysctl -a | grep bclon
>> > > vfs.zfs.bclone_enabled: 1
>> > >
>> > > I started a jail with poudriere to build a package. The jail uses null
>> > > mounts over ZFS.
>> > >
>> > > [root]# cu -s 115200 -l /dev/cuaU0
>> > > Connected
>> > >
>> > > db> bt
>> > > Tracing pid 95213 tid 100438 td 0xffff0000e1e97900
>> > > db_trace_self() at db_trace_self
>> > > db_stack_trace() at db_stack_trace+0x120
>> > > db_command() at db_command+0x2e4
>> > > db_command_loop() at db_command_loop+0x58
>> > > db_trap() at db_trap+0x100
>> > > kdb_trap() at kdb_trap+0x334
>> > > handle_el1h_sync() at handle_el1h_sync+0x18
>> > > --- exception, esr 0xf2000000
>> > > kdb_enter() at kdb_enter+0x48
>> > > vpanic() at vpanic+0x1dc
>> > > panic() at panic+0x48
>> > > data_abort() at data_abort+0x2fc
>> > > handle_el1h_sync() at handle_el1h_sync+0x18
>> > > --- exception, esr 0x96000004
>> > > rms_rlock() at rms_rlock+0x1c
>> > > zfs_clone_range() at zfs_clone_range+0x68
>> > > zfs_freebsd_copy_file_range() at zfs_freebsd_copy_file_range+0x19c
>> > > null_bypass() at null_bypass+0x118
>> > > vn_copy_file_range() at vn_copy_file_range+0x18c
>> > > kern_copy_file_range() at kern_copy_file_range+0x36c
>> > > sys_copy_file_range() at sys_copy_file_range+0x8c
>> > > do_el0_sync() at do_el0_sync+0x634
>> > > handle_el0_sync() at handle_el0_sync+0x48
>> > > --- exception, esr 0x56000000
>> > >
>> > >
>> > > Oh.. While typing this I rebooted the machine and it happened again. I
>> > > didn't start anything in particular although the machine runs some
>> > > jails.
>> > >
>> > > x0: 0x00000000000000e0
>> > >    x1: 0xffffa00090317a48
>> > >    x2: 0xffffa000f79d4f00
>> > >    x3: 0xffffa000c61a44a8
>> > >    x4: 0xffff0000deefe460 ($d.2 + 0xdd776560)
>> > >    x5: 0xffffa001250e4c00
>> > >    x6: 0xffff0000e54025b5 ($d.5 + 0xc)
>> > >    x7: 0x000000000000030a
>> > >    x8: 0xffff0000e1559000 ($d.2 + 0xdfdd1100)
>> > >    x9: 0x0000000000000001
>> > >   x10: 0x0000000000000000
>> > >   x11: 0x0000000000000001
>> > >   x12: 0x0000000000000002
>> > >   x13: 0x0000000000000000
>> > >   x14: 0x0000000000000001
>> > >   x15: 0x0000000000000000
>> > >   x16: 0xffff0000016dce88 (__stop_set_modmetadata_set + 0x1310)
>> > >   x17: 0xffff0000004e0d44 (rms_rlock + 0x0)
>> > >   x18: 0xffff0000deefe280 ($d.2 + 0xdd776380)
>> > >   x19: 0x0000000000000000
>> > >   x20: 0xffff0000deefe460 ($d.2 + 0xdd776560)
>> > >   x21: 0x7fffffffffffffff
>> > >   x22: 0xffffa00090317a48
>> > >   x23: 0xffffa000f79d4f00
>> > >   x24: 0xffffa001067ef910
>> > >   x25: 0x00000000000000e0
>> > >   x26: 0xffffa000158a8000
>> > >   x27: 0x0000000000000000
>> > >   x28: 0xffffa000158a8000
>> > >   x29: 0xffff0000deefe280 ($d.2 + 0xdd776380)
>> > >    sp: 0xffff0000deefe280
>> > >    lr: 0xffff000001623564 (zfs_clone_range + 0x6c)
>> > >   elr: 0xffff0000004e0d60 (rms_rlock + 0x1c)
>> > > spsr: 0x00000000a0000045
>> > >   far: 0x0000000000000108
>> > >   esr: 0x0000000096000004
>> > > panic: data abort in critical section or under mutex
>> > > cpuid = 1
>> > > time = 1699610885
>> > > KDB: stack backtrace:
>> > > db_trace_self() at db_trace_self
>> > > db_trace_self_wrapper() at db_trace_self_wrapper+0x38
>> > > vpanic() at vpanic+0x1a0
>> > > panic() at panic+0x48
>> > > data_abort() at data_abort+0x2fc
>> > > handle_el1h_sync() at handle_el1h_sync+0x18
>> > > --- exception, esr 0x96000004
>> > > rms_rlock() at rms_rlock+0x1c
>> > > zfs_clone_range() at zfs_clone_range+0x68
>> > > zfs_freebsd_copy_file_range() at zfs_freebsd_copy_file_range+0x19c
>> > > null_bypass() at null_bypass+0x118
>> > > vn_copy_file_range() at vn_copy_file_range+0x18c
>> > > kern_copy_file_range() at kern_copy_file_range+0x36c
>> > > sys_copy_file_range() at sys_copy_file_range+0x8c
>> > > do_el0_sync() at do_el0_sync+0x634
>> > > handle_el0_sync() at handle_el0_sync+0x48
>> > > --- exception, esr 0x56000000
>> > > KDB: enter: panic
>> > > [ thread pid 3792 tid 100394 ]
>> > > Stopped at      kdb_enter+0x48: str     xzr, [x19, #768]
>> > > db>
>> > >
>> > > I'll keep the debugger open for a while. Can I type something for
>> > > additional info?
>> > >
>> > > Regards,
>> > > Ronald.
>> >
>> > --
>> > Alexander Motin
>> 
>> 
>> 
> 
> 
> Hi,
> 
> Build a new kernel today.
> FreeBSD rpi4 15.0-CURRENT FreeBSD 15.0-CURRENT #20 main-051d69d6f8: Tue Nov 14 12:16:28 CET 2023     ronald@rpi4:/home/ronald/dev/freebsd/obj/home/ronald/dev/freebsd/src/arm64.aarch64/sys/GENERIC-NODEBUG arm64
> 
> x0: 0x00000000000008e0                                                                                                         
>   x1: 0xffffa0006ce1fb38                                                                                                                
>   x2: 0xffffa0006837a400                                                                                                                
>   x3: 0xffffa0012c503a48                                                                                                                
>   x4: 0xffff0000eb0ef430 (next_index + 0x815d790)                                                                                       
>   x5: 0xffffa00152636300                                                                                                                
>   x6: 0xffff0000e2e025b5 ($d.5 + 0xc)                                                                                                   
>   x7: 0x000000000000030a                                                                                                                
>   x8: 0xffff0000eb3212c0 (next_index + 0x838f620)                                                                                       
>   x9: 0x0000000000000001                                                                                                                
>  x10: 0x0000000000000000                                                                                                                
>  x11: 0x0000000000000001                                                                                                                
>  x12: 0x0000000000000002                                                                                                                
>  x13: 0x0000000000000000                                                                                                                
>  x14: 0x0000000000000001                                                                                                                
>  x15: 0x0000000000000000
>  x16: 0xffff0000016e5b58 (__stop_set_modmetadata_set + 0x1328)
>  x17: 0xffff0000004e0c28 (rms_rlock + 0x0)
>  x18: 0xffff0000eb0ef250 (next_index + 0x815d5b0)
>  x19: 0x0000000000000800
>  x20: 0xffff0000eb0ef430 (next_index + 0x815d790)
>  x21: 0x7fffffffffffffff
>  x22: 0xffffa0006ce1fb38
>  x23: 0xffffa0006837a400
>  x24: 0xffffa001ee486000
>  x25: 0x00000000000008e0
>  x26: 0xffffa000135ca000
>  x27: 0x0000000000000800
>  x28: 0xffffa000135ca000
>  x29: 0xffff0000eb0ef250 (next_index + 0x815d5b0)
>   sp: 0xffff0000eb0ef250
>   lr: 0xffff00000162bee8 (zfs_clone_range + 0x6c)
>  elr: 0xffff0000004e0c44 (rms_rlock + 0x1c)
> spsr: 0x00000000a0000045
>  far: 0x0000000000000908
>  esr: 0x0000000096000004
> panic: data abort in critical section or under mutex
> cpuid = 2
> time = 1699966486
> KDB: stack backtrace:
> db_trace_self() at db_trace_self
> db_trace_self_wrapper() at db_trace_self_wrapper+0x38
> vpanic() at vpanic+0x1a0
> panic() at panic+0x48
> data_abort() at data_abort+0x2fc
> handle_el1h_sync() at handle_el1h_sync+0x18
> --- exception, esr 0x96000004
> rms_rlock() at rms_rlock+0x1c
> zfs_clone_range() at zfs_clone_range+0x68
> zfs_freebsd_copy_file_range() at zfs_freebsd_copy_file_range+0x19c
> null_bypass() at null_bypass+0x118
> vn_copy_file_range() at vn_copy_file_range+0x1c0
> kern_copy_file_range() at kern_copy_file_range+0x36c
> sys_copy_file_range() at sys_copy_file_range+0x8c
> do_el0_sync() at do_el0_sync+0x634
> handle_el0_sync() at handle_el0_sync+0x48
> --- exception, esr 0x56000000
> KDB: enter: panic
> [ thread pid 3620 tid 100911 ]
> Stopped at      kdb_enter+0x48: str     xzr, [x19, #768]
> db>
> 
> This happens as soon as I start poudriere in a jenkins-agent jail.
> 
> AFAIK this includes the two recent vn_copy_file_range changes of Konstantin.
> 
> Next I will install a GENERIC kernel instead of GENERIC-NODEBUG.
> 
> Regards,
> Ronald.
>  


This is while running a DEBUG kernel.
FreeBSD 15.0-CURRENT #5 main-20e1f207cc: Tue Nov 14 15:44:40 CET 2023
    ronald@rpi4:/home/ronald/dev/freebsd/obj/home/ronald/dev/freebsd/src/arm64.aarch64/sys/GENERIC arm64

acquiring duplicate lock of same type: "vnode interlock"                                                                         
 1st vnode interlock @ /home/ronald/dev/freebsd/src/sys/fs/nullfs/null_vnops.c:370                                                      
 2nd vnode interlock @ /home/ronald/dev/freebsd/src/sys/fs/nullfs/null_vnops.c:370                                                      
stack backtrace:                                                                                                                        
#0 0xffff00000050798c at witness_debugger+0x60                                                                                          
#1 0xffff00000046c25c at __mtx_lock_flags+0xac                                                                                          
#2 0xffff0000e3014f14 at null_add_writecount+0x40                                                                                       
#3 0xffff0000e3014f44 at null_add_writecount+0x70                                                                                       
#4 0xffff0000005a08b4 at vn_open_vnode+0x278                                                                                            
#5 0xffff0000005a019c at vn_open_cred+0x484                                                                                             
#6 0xffff000000596cac at kern_openat+0x24c                                                                                              
#7 0xffff0000008443f4 at do_el0_sync+0x59c                                                                                              
#8 0xffff00000081e91c at handle_el0_sync+0x48                                                                                           
  x0: 0x0000000000000000                                                                                                                
  x1: 0xffff000000a2dfeb (console_pausestr + 0xab0)                                                                                     
  x2: 0xffff0000009715fb (cam_status_table + 0x14a13)                                                                                   
  x3: 0xffffa000ba780d18                                                                                                                
  x4: 0xffff0000deef8430 (ucom_cons_softc + 0xdd66faa0)                                                                                 
  x5: 0xffffa001200d4900                                                                                                                
  x6: 0x0000808080808080                                                                                                                
  x7: 0xffffa001200d4900                                                                                                                
  x8: 0x0000000000000000                                                                                                                
  x9: 0x0000000000000000                                                                                                                
 x10: 0x0000000000000001                                                                                                                
 x11: 0x0000000000000001                                                                                                                
 x12: 0x0000000000000002                                                                                                                
 x13: 0x0000000000000000                                                                                                                
 x14: 0x0000000000010000                                                                                                                
 x15: 0x0000000000000001
 x16: 0xffff00000172b258 (__stop_set_modmetadata_set + 0x1360)
 x17: 0xffff00000048ba24 (rms_rlock + 0x0)
 x18: 0xffff0000deef8240 (ucom_cons_softc + 0xdd66f8b0)
 x19: 0xffff0000e2ef9fd0 (ucom_cons_softc + 0xe1671640)
 x20: 0xffff0000deef8430 (ucom_cons_softc + 0xdd66faa0)
 x21: 0x7fffffffffffffff
 x22: 0xffffa000b9a169a8
 x23: 0xffffa0018c7e4d00
 x24: 0xffffa001a377acb0
 x25: 0xffff0000e2ef9fd0 (ucom_cons_softc + 0xe1671640)
 x26: 0xffffa0001480f000
 x27: 0xffff0000e2ef9ef0 (ucom_cons_softc + 0xe1671560)
 x28: 0xffffa0001480f000
 x29: 0xffff0000deef8240 (ucom_cons_softc + 0xdd66f8b0)
  sp: 0xffff0000deef8240
  lr: 0xffff00000048ba4c (rms_rlock + 0x28)
 elr: 0xffff00000048ba90 (rms_rlock + 0x6c)
spsr: 0x0000000000000045
 far: 0x0000000000000000
 esr: 0x0000000096000004
panic: data abort in critical section or under mutex
cpuid = 0
time = 1699974087
KDB: stack backtrace:
db_trace_self() at db_trace_self
db_trace_self_wrapper() at db_trace_self_wrapper+0x38
vpanic() at vpanic+0x1a0
panic() at panic+0x48
data_abort() at data_abort+0x31c
handle_el1h_sync() at handle_el1h_sync+0x18
--- exception, esr 0x96000004
rms_rlock() at rms_rlock+0x6c
zfs_clone_range() at zfs_clone_range+0x68
zfs_freebsd_copy_file_range() at zfs_freebsd_copy_file_range+0x1bc
null_bypass() at null_bypass+0x118
vn_copy_file_range() at vn_copy_file_range+0x1b0
kern_copy_file_range() at kern_copy_file_range+0x37c
sys_copy_file_range() at sys_copy_file_range+0x8c
do_el0_sync() at do_el0_sync+0x59c
handle_el0_sync() at handle_el0_sync+0x48
--- exception, esr 0x56000000
KDB: enter: panic
[ thread pid 3703 tid 100223 ]
Stopped at      kdb_enter+0x48: str     xzr, [x19, #896]
db>


I have coredump/textdump files and can DM if needed.

BTW: while typing this the RPI rebooted poudriere was restarted by Jenkins and it now logs this message (not a panic):
acquiring duplicate lock of same type: "vnode interlock"
 1st vnode interlock @ /home/ronald/dev/freebsd/src/sys/fs/nullfs/null_vnops.c:370
 2nd vnode interlock @ /home/ronald/dev/freebsd/src/sys/fs/nullfs/null_vnops.c:370
stack backtrace:
#0 0xffff00000050798c at witness_debugger+0x60
#1 0xffff00000046c25c at __mtx_lock_flags+0xac
#2 0xffff0000e5214f14 at null_add_writecount+0x40
#3 0xffff0000e5214f44 at null_add_writecount+0x70
#4 0xffff0000005a08b4 at vn_open_vnode+0x278
#5 0xffff0000005a019c at vn_open_cred+0x484
#6 0xffff000000596cac at kern_openat+0x24c
#7 0xffff0000008443f4 at do_el0_sync+0x59c
#8 0xffff00000081e91c at handle_el0_sync+0x48

The last duplicate lock log is with "vfs.zfs.bclone_enabled: 0".

The panics are with "vfs.zfs.bclone_enabled: 1".

Regards,
Ronald.