[LU-17705] replace synchronize_rcu() with rcu_barrier()

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

synchronize_rcu() doesn't wait for all in-flight callback completion:

[   30.290958] ------------[ cut here ]------------
[   30.291101] kernel BUG at mm/slab.c:3715!
[   30.291226] invalid opcode: 0000 [#1] PREEMPT SMP
[   30.291386] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G        W  O     --------- -  - 4.18.0 #38
[   30.291653] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014
[   30.291911] RIP: 0010:kmem_cache_free.cold.23+0x19/0x1b
[   30.292051] Code: 48 c7 c0 f2 ff ff ff eb c8 48 c7 c0 ea ff ff ff c3 49 89 f9 49 89 f8 48 89 f9 57 48 89 f2 48 c7 c7 50 f9 e4 b8 e8 d0 d2 eb ff <0f> 0b 48 8b 73 58 89 c2 48 c7 c7 80 f9 e4 b8 f7 da e8 ba d2 eb ff
[   30.292546] RSP: 0018:ffff9ebd77d05ec8 EFLAGS: 00010282
[   30.292684] RAX: 000000000000007a RBX: 5a5a5a5a5a5a5a5a RCX: 0000000000000102
[   30.292888] RDX: 0000000080000102 RSI: ffffffffb8e45e66 RDI: 00000000ffffffff
[   30.293098] RBP: ffff9ebc41b310a0 R08: 0000000000000000 R09: 0000000000000000
[   30.293313] R10: ffff9ebd77d05d18 R11: ffff9ebd77d05d10 R12: 0000000000000158
[   30.293521] R13: ffffffffb93f55a0 R14: 0000000000000000 R15: 0000000000000001
[   30.293777] FS:  0000000000000000(0000) GS:ffff9ebd77d00000(0000) knlGS:0000000000000000
[   30.294024] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   30.294222] CR2: 00007ffc21669f60 CR3: 000000014dab3000 CR4: 0000000000350ea0
[   30.294459] Call Trace:
[   30.294539]  <IRQ>
[   30.294617]  rcu_core+0x315/0x970
[   30.294732]  ? rcu_core+0x2e8/0x970
[   30.294849]  __do_softirq+0xd2/0x4cd
[   30.294964]  irq_exit_rcu+0xda/0xe0
[   30.295079]  irq_exit+0x5/0x20
[   30.295191]  smp_apic_timer_interrupt+0xbf/0x290
[   30.295358]  apic_timer_interrupt+0xf/0x20
[   30.295471]  </IRQ>

Issue Links

• is related to: LU-17076 ptlrpc_nrs_req_stop_nolock() use after free with ORR NRS policy