On 11.09.19 г. 11:00 ч., Abdul Haleem wrote:
> On Tue, 2019-09-03 at 13:39 +0300, Nikolay Borisov wrote:
>>
>> On 3.09.19 г. 11:55 ч., Abdul Haleem wrote:
>>> Greeting's
>>>
>>> Mainline kernel panics with LTP/fs_fill-dir tests for btrfs file system on
>>> my P9 box running mainline kernel 5.3.0-rc5
>>>
>>> BUG_ON was first introduced by below commit
>>>
>>> commit 00801ae4bb2be5f5af46502ef239ac5f4b536094
>>> Author: David Sterba <dste...@suse.com>
>>> Date: Thu May 2 16:53:47 2019 +0200
>>>
>>> btrfs: switch extent_buffer write_locks from atomic to int
>>>
>>> The write_locks is either 0 or 1 and always updated under the lock,
>>> so we don't need the atomic_t semantics.
>>>
>>> Reviewed-by: Nikolay Borisov <nbori...@suse.com>
>>> Signed-off-by: David Sterba <dste...@suse.com>
>>>
>>> diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
>>> index 2706676279..98fccce420 100644
>>> --- a/fs/btrfs/locking.c
>>> +++ b/fs/btrfs/locking.c
>>> @@ -58,17 +58,17 @@ static void btrfs_assert_tree_read_locked(struct
>>> extent_buffer *eb)
>>>
>>> static void btrfs_assert_tree_write_locks_get(struct extent_buffer *eb)
>>> {
>>> - atomic_inc(&eb->write_locks);
>>> + eb->write_locks++;
>>> }
>>>
>>> static void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb)
>>> {
>>> - atomic_dec(&eb->write_locks);
>>> + eb->write_locks--;
>>> }
>>>
>>> void btrfs_assert_tree_locked(struct extent_buffer *eb)
>>> {
>>> - BUG_ON(!atomic_read(&eb->write_locks));
>>> + BUG_ON(!eb->write_locks);
>>> }
>>>
>>>
>>> tests logs:
>>> avocado-misc-tests/io/disk/ltp_fs.py:LtpFs.test_fs_run;fs_fill-dir-ext3-61cd:
>>> [ 3376.022096] EXT4-fs (nvme0n1): mounting ext3 file system using the
>>> ext4 subsystem
>>> EXT4-fs (nvme0n1): mounted filesystem with ordered data mode. Opts: (null)
>>> EXT4-fs (loop1): mounting ext2 file system using the ext4 subsystem
>>> EXT4-fs (loop1): mounted filesystem without journal. Opts: (null)
>>> EXT4-fs (loop1): mounting ext3 file system using the ext4 subsystem
>>> EXT4-fs (loop1): mounted filesystem with ordered data mode. Opts: (null)
>>> EXT4-fs (loop1): mounted filesystem with ordered data mode. Opts: (null)
>>> XFS (loop1): Mounting V5 Filesystem
>>> XFS (loop1): Ending clean mount
>>> XFS (loop1): Unmounting Filesystem
>>> BTRFS: device fsid 7c08f81b-6642-4a06-9182-2884e80d56ee devid 1 transid 5
>>> /dev/loop1
>>> BTRFS info (device loop1): disk space caching is enabled
>>> BTRFS info (device loop1): has skinny extents
>>> BTRFS info (device loop1): enabling ssd optimizations
>>> BTRFS info (device loop1): creating UUID tree
>>> ------------[ cut here ]------------
>>> kernel BUG at fs/btrfs/locking.c:71!
>>> Oops: Exception in kernel mode, sig: 5 [#1]
>>> LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
>>> Dumping ftrace buffer:
>>> (ftrace buffer empty)
>>> Modules linked in: fuse(E) vfat(E) fat(E) btrfs(E) xor(E)
>>> zstd_decompress(E) zstd_compress(E) raid6_pq(E) xfs(E) raid0(E)
>>> linear(E) dm_round_robin(E) dm_queue_length(E) dm_service_time(E)
>>> dm_multipath(E) loop(E) rpadlpar_io(E) rpaphp(E) lpfc(E) bnx2x(E)
>>> xt_CHECKSUM(E) xt_MASQUERADE(E) tun(E) bridge(E) stp(E) llc(E) kvm_pr(E)
>>> kvm(E) tcp_diag(E) udp_diag(E) inet_diag(E) unix_diag(E)
>>> af_packet_diag(E) netlink_diag(E) ip6t_rpfilter(E) ipt_REJECT(E)
>>> nf_reject_ipv4(E) ip6t_REJECT(E) nf_reject_ipv6(E) xt_conntrack(E)
>>> ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) ip6table_nat(E)
>>> ip6table_mangle(E) ip6table_security(E) ip6table_raw(E) iptable_nat(E)
>>> nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E)
>>> iptable_mangle(E) iptable_security(E) iptable_raw(E) ebtable_filter(E)
>>> ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) sunrpc(E)
>>> raid10(E) xts(E) pseries_rng(E) vmx_crypto(E) sg(E) uio_pdrv_genirq(E)
>>> uio(E) binfmt_misc(E) sch_fq_codel(E) ip_tables(E)
>>> ext4(E) mbcache(E) jbd2(E) sr_mod(E) cdrom(E) sd_mod(E) ibmvscsi(E)
>>> scsi_transport_srp(E) ibmveth(E) nvmet_fc(E) nvmet(E) nvme_fc(E)
>>> nvme_fabrics(E) scsi_transport_fc(E) mdio(E) libcrc32c(E) ptp(E)
>>> pps_core(E) nvme(E) nvme_core(E) dm_mirror(E) dm_region_hash(E)
>>> dm_log(E) dm_mod(E) [last unloaded: lpfc]
>>> CPU: 14 PID: 1803 Comm: kworker/u32:8 Tainted: G E
>>> 5.3.0-rc5-autotest-autotest #1
>>> Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
>>> NIP: c00800000164dd70 LR: c00800000164df00 CTR: c000000000a817a0
>>> REGS: c00000000260b5d0 TRAP: 0700 Tainted: G E
>>> (5.3.0-rc5-autotest-autotest)
>>> MSR: 8000000102029033 <SF,VEC,EE,ME,IR,DR,RI,LE,TM[E]> CR: 22444082 XER:
>>> 00000000
>>> CFAR: c00800000164defc IRQMASK: 0
>>> GPR00: c0080000015c55f4 c00000000260b860 c008000001703b00 c000000267a29af0
>>> GPR04: 0000000000000000 0000000000000001 0000000000000000 0000000000000000
>>> GPR08: 0000000000000000 0000000000000001 0000000000000000 0000000000000004
>>> GPR12: 0000000000004000 c00000001ec58e00 0000000000000000 0000000000000000
>>> GPR16: 0000000000010000 0000000000000004 0000000000000001 0000000000000001
>>> GPR20: 0000000000000000 0000000000000001 000000003e0f83e1 c00000025a7cbef0
>>> GPR24: c00000000260ba26 0000000040000000 c0000000014a26e8 0000000000000003
>>> GPR28: 0000000000000004 c00000025f2010a0 c000000267a29af0 0000000000000000
>>> NIP [c00800000164dd70] btrfs_assert_tree_locked+0x10/0x20 [btrfs]
>>> LR [c00800000164df00] btrfs_set_lock_blocking_write+0x60/0x100 [btrfs]
>>> Call Trace:
>>> [c00000000260b860] [c00000000260b8e0] 0xc00000000260b8e0 (unreliable)
>>> [c00000000260b890] [c0080000015c55f4] btrfs_set_path_blocking+0xb4/0xc0
>>> [btrfs]
>>> [c00000000260b8e0] [c0080000015cb808] btrfs_search_slot+0x8e8/0xb80 [btrfs]
>>
>> Can you provide the line numbers btrfs_search_slot+0x8e8/0xb80
>> corresponds to?
>
> btrfs_search_slot+0x8e8/0xb80 maps to fs/btrfs/ctree.c:2751
> write_lock_level = BTRFS_MAX_LEVEL;
> 9a70: 08 00 40 39 li r10,8
> 9a74: 08 00 a0 3a li r21,8
>> 9a78: 6c 00 41 91 stw r10,108(r1)
> 9a7c: 1c f8 ff 4b b 9298 <btrfs_search_slot+0x108>
> b = btrfs_root_node(root);
Can you print the output of 'l *(btrfs_search_slot+0x8e8)' in gdb or
scripts/faddr2line . Because neither this nor the sent objdump is of
much help.
