[PATCH] erofs: fix PSI memstall accounting

[Max Kellermann]

On Tue, Dec 3, 2024 at 2:30 PM Max Kellermann <max.kellermann at ionos.com> wrote:
> __builtin_return_address(1) instantly crashes the kernel

I was able to capture the __builtin_return_address crash on a serial
console (this has nothing to do with the PSI memstall bug):

[16438.331677] BUG: kernel NULL pointer dereference, address: 0000000000000008
[16438.338693] #PF: supervisor read access in kernel mode
[16438.343866] #PF: error_code(0x0000) - not-present page
[16438.349038] PGD 0 P4D 0
[16438.351588] Oops: Oops: 0000 [#1] SMP PTI
[16438.355625] CPU: 18 UID: 2147486501 PID: 23486 Comm: less Not
tainted 6.11.10-cm4all4-hp+ #291
[16438.364297] Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380
Gen10, BIOS U30 09/05/2019
[16438.372880] RIP: 0010:psi_memstall_enter+0x7f/0xa0
[16438.377708] Code: 89 df 80 8b 19 05 00 00 01 48 8b 45 08 48 89 83
c0 08 00 00 48 8b 45 00 48 8b 40 08 48 89 83 c8 08 00 00 48 8b 45 00
48 8b 00 <48> 8b 40 08 48 89 83 d0 08 00 00 e8 d1 fe ff ff 4c 89 e7 e8
29 28
[16438.396609] RSP: 0000:ffff9ee683bc7bd0 EFLAGS: 00010002
[16438.401869] RAX: 0000000000000000 RBX: ffff90c70c291740 RCX: 0000000000000001
[16438.409052] RDX: 000000000000000a RSI: 0000000000000000 RDI: ffff90c70c291740
[16438.416234] RBP: ffff9ee683bc7be0 R08: 000000000007cec1 R09: 0000000000000007
[16438.423418] R10: ffff90c727d83678 R11: 0000000000000000 R12: ffff9124bd0ae000
[16438.430600] R13: 0000000000000014 R14: ffff9ee683bc7ce8 R15: 0000000000000000
[16438.437785] FS:  00007ff15f1f4740(0000) GS:ffff9124bd080000(0000)
knlGS:0000000000000000
[16438.445929] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[16438.451714] CR2: 0000000000000008 CR3: 000000010c54a002 CR4: 00000000007706f0
[16438.458896] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[16438.466079] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[16438.473263] PKRU: 55555554
[16438.475984] Call Trace:
[16438.478446]  <TASK>
[16438.480557]  ? __die+0x1f/0x60
[16438.483636]  ? page_fault_oops+0x15c/0x450
[16438.487761]  ? exc_page_fault+0x5e/0x100
[16438.491710]  ? asm_exc_page_fault+0x22/0x30
[16438.495923]  ? psi_memstall_enter+0x7f/0xa0
[16438.500135]  read_pages+0x205/0x220
[16438.503647]  ? free_unref_page+0x2c1/0x420
[16438.507771]  page_cache_ra_order+0x1d3/0x2b0
[16438.512069]  filemap_fault+0x548/0xba0
[16438.515845]  __do_fault+0x32/0x90
[16438.519182]  do_fault+0x2a1/0x4a0
[16438.522519]  __handle_mm_fault+0x337/0x1ca0
[16438.526730]  handle_mm_fault+0x128/0x260
[16438.530677]  do_user_addr_fault+0x1d8/0x5b0
[16438.534889]  exc_page_fault+0x5e/0x100
[16438.538663]  asm_exc_page_fault+0x22/0x30
[16438.542697] RIP: 0033:0x55ebb60829a0
[16438.546298] Code: Unable to access opcode bytes at 0x55ebb6082976.
[16438.552519] RSP: 002b:00007fffd2a03658 EFLAGS: 00010246
[16438.557779] RAX: 0000000000000016 RBX: 000055ebdb88b410 RCX: 000055ebdb88b410
[16438.564963] RDX: 0000000000000ee4 RSI: 000055ec5b0b1e30 RDI: 000055ebdb88b910
[16438.572147] RBP: 0000000000000010 R08: 00000000ffffffff R09: 0000000000000000
[16438.579331] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000046
[16438.586514] R13: 000055ebb6099e6c R14: 000055ebb6099c93 R15: 00007fffd2a03706
[16438.593697]  </TASK>
[16438.595895] Modules linked in:
[16438.598970] CR2: 0000000000000008
[16438.602307] ---[ end trace 0000000000000000 ]---