Hi David & netfs developers,
I tried the new Linux kernel 6.12 today and it quickly reported a bug:
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WARNING: CPU: 13 PID: 0 at kernel/softirq.c:361 __local_bh_enable_ip+0x37/0x50
Modules linked in:
CPU: 13 UID: 0 PID: 0 Comm: swapper/13 Not tainted 6.12.0-cm4all1-hp+ #236
Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS
U30 09/05/2019
RIP: 0010:__local_bh_enable_ip+0x37/0x50
Code: 00 0f 00 75 25 83 ee 01 f7 de 65 01 35 2a 93 d8 70 65 f7 05 1f
93 d8 70 00 ff ff 00 74 10 65 ff 0d 16 93 d8 70 c3 cc cc cc cc <0f> 0b
eb d7 65 66 83 3d 24 93 d8 70 00 74 e5 e8 45 ff ff ff eb de
RSP: 0018:ffff979300464d30 EFLAGS: 00010006
RAX: dead000000000122 RBX: ffff8c5cd1045b00 RCX: ffff8c5cdeff7800
RDX: ffff8c5d022f91f0 RSI: 0000000000000200 RDI: ffffffff8f5ee1cc
RBP: 0000000000000000 R08: 0000000000000002 R09: ffff8cba7cf6eb68
R10: ffffffff910621e0 R11: 0000000000000001 R12: ffff8c5d022f9368
R13: 0000000000001000 R14: ffff8c5d022f9368 R15: 0000000000001000
FS: 0000000000000000(0000) GS:ffff8cba7cf40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ea9986d368 CR3: 000000603ee2e005 CR4: 00000000007706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
? __warn+0x81/0x110
? __local_bh_enable_ip+0x37/0x50
? report_bug+0x14c/0x170
? handle_bug+0x53/0x90
? exc_invalid_op+0x13/0x60
? asm_exc_invalid_op+0x16/0x20
? netfs_consume_read_data.isra.0+0x3fc/0xa70
? __local_bh_enable_ip+0x37/0x50
netfs_consume_read_data.isra.0+0x3fc/0xa70
? __pfx_cachefiles_read_complete+0x10/0x10
netfs_read_subreq_terminated+0x265/0x360
cachefiles_read_complete+0x45/0xf0
iomap_dio_bio_end_io+0x122/0x160
blk_update_request+0xf1/0x3e0
scsi_end_request+0x27/0x190
scsi_io_completion+0x43/0x6c0
pqi_irq_handler+0x108/0xcd0
__handle_irq_event_percpu+0x43/0x160
handle_irq_event+0x27/0x70
handle_edge_irq+0x82/0x220
__common_interrupt+0x37/0xb0
common_interrupt+0x74/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40
RIP: 0010:cpuidle_enter_state+0xba/0x3c0
Code: 00 e8 7a 06 1d ff e8 45 f7 ff ff 8b 53 04 49 89 c5 0f 1f 44 00
00 31 ff e8 83 38 1c ff 45 84 ff 0f 85 16 01 00 00 fb 45 85 f6 <0f> 88
76 01 00 00 48 8b 04 24 49 63 ce 48 6b d1 68 49 29 c5 48 89
RSP: 0018:ffff97930015fe98 EFLAGS: 00000206
RAX: ffff8cba7cf40000 RBX: ffffb792fe94f250 RCX: 000000000000001f
RDX: 000000000000000d RSI: 0000000037c86db9 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000002 R09: 0000000000000020
R10: 0000000000000003 R11: 0000000000000015 R12: ffffffff9125b220
R13: 000006c7b80e3e03 R14: 0000000000000003 R15: 0000000000000000
? cpuidle_enter_state+0xad/0x3c0
cpuidle_enter+0x29/0x40
do_idle+0x19f/0x200
cpu_startup_entry+0x25/0x30
start_secondary+0xf3/0x100
common_startup_64+0x13e/0x148
</TASK>
---[ end trace 0000000000000000 ]---
Apparently, the netfs code doesn't want to be called from hardirq
context, but the cachefiles read completion callback may run in a
hardirq handler.
This source file is new in 6.12, so this regression may have been
caused by David Howell's commit ee4cdf7ba857 ("netfs: Speed up
buffered reading").
Max
