On Wed, 10 Jul 2019, Peter Zijlstra wrote: > > > BUG: unable to handle page fault for address: ffffffff9edc1598 > > > #PF: supervisor write access in kernel mode > > > #PF: error_code(0x0003) - permissions violation > > > PGD 1a20c067 P4D 1a20c067 PUD 1a20d063 PMD 8000000019e000e1 > > > Oops: 0003 [#1] SMP PTI > > > 2 PID: 151 Comm: systemd-udevd Not tainted 5.2.0+ #54 > > > Hardware name: LENOVO 20175/INVALID, BIOS 66CN54WW 01/21/2013 > > > RIP: 0010:static_key_set_mod.isra.0+0x10/0x30 > > > Code: 48 8b 37 83 e6 03 48 09 c6 48 89 37 c3 66 66 2e 0f 1f 84 00 00 00 > > > 00 00 66 90 48 89 f0 a8 03 75 0d 48 8b 37 83 e6 03 48 09 c6 <48> 89 37 c3 > > > 0f 0b 48 8b 37 83 e6 03 48 09 c6 48 89 37 c3 66 66 2e > > > RSP: 0000:ffffa606c032bc98 EFLAGS: 00010286 > > > RAX: ffff9981ddce30a0 RBX: ffffffff9edc1590 RCX: 0000000000000000 > > > RDX: 0000000000000020 RSI: ffff9981ddce30a0 RDI: ffffffff9edc1598 > > > RBP: ffffffffc06f4000 R08: ffff9981e6003980 R09: ffff9981ddce30a0 > > > R10: 0000000000000000 R11: 0000000000028b56 R12: ffffffffc06f8880 > > > R13: ffff9981ddce3080 R14: ffffffffc06f4008 R15: ffffffffc06f6dc0 > > > FS: 00007f992dd9a680(0000) GS:ffff9981e7080000(0000) > > > knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: ffffffff9edc1598 CR3: 00000002233aa001 CR4: 00000000001606e0 > > > Call Trace: > > > jump_label_module_notify+0x1e7/0x2b0 > > > notifier_call_chain+0x44/0x70 > > > blocking_notifier_call_chain+0x43/0x60 > > > load_module+0x1bcb/0x2490 > > > ? vfs_read+0x11f/0x150 > > > ? __do_sys_finit_module+0xbf/0xe0 > > > __do_sys_finit_module+0xbf/0xe0 > > > do_syscall_64+0x43/0x110 > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > > > > > Josh, didn't you mention that yesterday or so? > > > > That's what Tony yesterday indicated on IRC that his system is suffering > > from as well. > > > > Adding Daniel to check whether this couldn't be some fallout of jumplabel > > batching. > > AFAICT this is _before_ we get to patching. The function that explodes > is static_key_set_mod(), as called from jump_label_add_module(). > > What that function does is for all patch sites in the module, find the > corresponding key; if that key is not also in that module, allocate a > static_key_mod structure and link the module entries to the key. Such > that we can find all instances from a given key. > > I don't think anything here has changed in a while.
Hm, and it seems to explode on dereferencing the static_key* in %rsi 21: 48 8b 37 mov (%rdi),%rsi 24: 83 e6 03 and $0x3,%esi 27: 48 09 c6 or %rax,%rsi 2a:* 48 89 37 mov %rsi,(%rdi) <-- trapping instruction which looks odd, as it derefenced it successfully just 3 instructions ago. -- Jiri Kosina SUSE Labs
