ktime_get_ts64() splat during resume

[Borislav Petkov]

Hi guys,

look what I've found this morning during resume:

[   45.732934] PM: Image restored successfully.
[   45.738064] PM: Basic memory bitmaps freed
[   45.742914] Restarting tasks ... 
[   45.746236] BUG: unable to handle kernel done.
[   45.752542] NULL pointer dereference at 0000000000000001
[   45.752544] IP: [<0000000000000001>] 0x1
[   45.752547] PGD 37922067 PUD 3791a067 PMD 0 
[   45.752548] Oops: 0010 [#1] PREEMPT SMP
[   45.752557] Modules linked in: binfmt_misc ipv6 vfat fat amd64_edac_mod edac_mce_amd fuse dm_crypt dm_mod kvm_amd kvm amdkfd amd_iommu_v2 irqbypass crc32_pclmul radeon aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd fam15h_power k10temp acpi_cpufreq
[   45.752559] CPU: 2 PID: 1 Comm: init Not tainted 4.7.0-rc3+ #1
[   45.752560] Hardware name: To be filled by O.E.M. To be filled by O.E.M./M5A97 EVO R2.0, BIOS 1503 01/16/2013
[   45.752560] task: ffff88042b958000 ti: ffff88042b954000 task.ti: ffff88042b954000
[   45.752562] RIP: 0010:[<0000000000000001>]  [<0000000000000001>] 0x1
[   45.752562] RSP: 0018:ffff88042b957e50  EFLAGS: 00010246
[   45.752563] RAX: 0000000000000000 RBX: ffffffff81181e1e RCX: fffffffffffffdfe
[   45.752564] RDX: ffff88042b958000 RSI: ffff88042b954000 RDI: ffffffff8168aeac
[   45.752564] RBP: 0000000000000430 R08: 0000000000000000 R09: 0000000000000002
[   45.752565] R10: 0000000000000000 R11: 0000000000000001 R12: ffffff9c00000002
[   45.752565] R13: ffff88042b09a300 R14: ffffffff811782bf R15: 0000000000000011
[   45.752566] FS:  00007f9d470ab800(0000) GS:ffff88043dc80000(0000) knlGS:0000000000000000
[   45.752567] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   45.752567] CR2: 0000000000000001 CR3: 0000000037923000 CR4: 00000000000406e0
[   45.752568] Stack:
[   45.752569]  0000000000001180 0000000000000000 ffff88042b957e88 ffffffff810bb33a
[   45.752570]  00000000fffffdfe ffff88042b957f00 00007ffcfa91b1f0 ffff88042b957ee8
[   45.752571]  ffffffff81185fc7 0000000000000003 0000000021b8e1cd 0000000000000003
[   45.752571] Call Trace:
[   45.752576]  [<ffffffff810bb33a>] ? ktime_get_ts64+0x4a/0xf0
[   45.752578]  [<ffffffff81185fc7>] ? poll_select_copy_remaining+0xe7/0x130
[   45.752581]  [<ffffffff8100263a>] ? exit_to_usermode_loop+0x8a/0xb0
[   45.752582]  [<ffffffff81002a6b>] ? syscall_return_slowpath+0x5b/0x70
[   45.752584]  [<ffffffff8168b372>] ? entry_SYSCALL_64_fastpath+0xa5/0xa7
[   45.752587] Code:  Bad RIP value.
[   45.752588] RIP  [<0000000000000001>] 0x1
[   45.752589]  RSP <ffff88042b957e50>
[   45.752589] CR2: 0000000000000001
[   45.752597] ---[ end trace 5334fe9eec2bfca9 ]---
[   45.752737] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[   45.752737] 
[   45.758773] Kernel Offset: disabled

rIP is gone.

That's rc3+tip/master from Wed:

commit 043ae67b6fdd9db7fb54564124d2f2fa833c5ee6 (refs/remotes/tip/master)
Merge: 0bbd6fbba8c7 00688272157d
Author: Ingo Molnar <mingo@xxxxxxxxxx>
Date:   Wed Jun 15 12:53:02 2016 +0200

    Merge branch 'x86/platform'

The top function in the stacktrace is:

[   45.752576]  [<ffffffff810bb33a>] ? ktime_get_ts64+0x4a/0xf0

and that address is:

ffffffff810bb2f0 <ktime_get_ts64>:
ffffffff810bb2f0:       e8 6b 21 5d 00          callq  ffffffff8168d460 <__fentry__>
ffffffff810bb2f5:       55                      push   %rbp
ffffffff810bb2f6:       8b 05 14 52 bf 00       mov    0xbf5214(%rip),%eax        # ffffffff81cb0510 <timekeeping_suspended>
ffffffff810bb2fc:       48 89 e5                mov    %rsp,%rbp
ffffffff810bb2ff:       41 55                   push   %r13
ffffffff810bb301:       85 c0                   test   %eax,%eax
ffffffff810bb303:       41 54                   push   %r12
ffffffff810bb305:       53                      push   %rbx
ffffffff810bb306:       48 89 fb                mov    %rdi,%rbx
ffffffff810bb309:       0f 85 b6 00 00 00       jne    ffffffff810bb3c5 <ktime_get_ts64+0xd5>
ffffffff810bb30f:       45 31 e4                xor    %r12d,%r12d
ffffffff810bb312:       44 8b 2d a7 a9 f5 00    mov    0xf5a9a7(%rip),%r13d        # ffffffff82015cc0 <tk_core>
ffffffff810bb319:       41 f6 c5 01             test   $0x1,%r13b
ffffffff810bb31d:       0f 85 9b 00 00 00       jne    ffffffff810bb3be <ktime_get_ts64+0xce>
ffffffff810bb323:       48 8b 05 0e aa f5 00    mov    0xf5aa0e(%rip),%rax        # ffffffff82015d38 <tk_core+0x78>
ffffffff810bb32a:       48 89 03                mov    %rax,(%rbx)
ffffffff810bb32d:       48 8b 3d 94 a9 f5 00    mov    0xf5a994(%rip),%rdi        # ffffffff82015cc8 <tk_core+0x8>
ffffffff810bb334:       ff 15 96 a9 f5 00       callq  *0xf5a996(%rip)        # ffffffff82015cd0 <tk_core+0x10>
ffffffff810bb33a:       48 2b 05 9f a9 f5 00    sub    0xf5a99f(%rip),%rax        # ffffffff82015ce0 <tk_core+0x20>	<--- HERE
ffffffff810bb341:       48 8b 15 90 a9 f5 00    mov    0xf5a990(%rip),%rdx        # ffffffff82015cd8 <tk_core+0x18>
ffffffff810bb348:       44 8b 05 99 a9 f5 00    mov    0xf5a999(%rip),%r8d        # ffffffff82015ce8 <tk_core+0x28>
ffffffff810bb34f:       48 8b 35 9a a9 f5 00    mov    0xf5a99a(%rip),%rsi        # ffffffff82015cf0 <tk_core+0x30>
ffffffff810bb356:       8b 0d 90 a9 f5 00       mov    0xf5a990(%rip),%ecx        # ffffffff82015cec <tk_core+0x2c>
ffffffff810bb35c:       48 8b 3d e5 a9 f5 00    mov    0xf5a9e5(%rip),%rdi        # ffffffff82015d48 <tk_core+0x88>

i.e., right after the call to tkr->read():

static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
{
        cycle_t cycle_now, delta;

        /* read clocksource */
        cycle_now = tkr->read(tkr->clock);
		    ^^^^^^^^^^

Ring any bells about something corrupting tk_core.timekeeper.tkr_mono or
it being uninitialized after suspend?

Thanks.

-- 
Regards/Gruss,
    Boris.

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