Hi!
commit f208820a321f9b23d77d7eed89945d862d62a3ed
Author: David Woodhouse <dwmw@xxxxxxxxxxxx>
Date: Sat Feb 10 23:39:23 2018 +0000
Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()"
This reverts commit 64e16720ea0879f8ab4547e3b9758936d483909b.
We cannot call C functions like that, without marking all the
call-clobbered registers as, well, clobbered. We might have got away
with it for now because the __ibp_barrier() function was *fairly*
unlikely to actually use any other registers. But no. Just no.
causes a crash here. When I revert this revert on top of Linus' tree, it works fine.
Host is v4.13 + qemu-2.9.1 (openSUSE).
[ 2.776181] general protection fault: 0000 [#1] SMP PTI
[ 2.777146] Modules linked in:
[ 2.777422] CPU: 1 PID: 1208 Comm: systemd-journal Not tainted 4.16.0-rc1+ #111
[ 2.778079] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
[ 2.778988] RIP: 0010:switch_mm_irqs_off+0x2f1/0x3c0
[ 2.779372] RSP: 0018:ffffac6f0053bd60 EFLAGS: 00010097
[ 2.779808] RAX: 0000000000000001 RBX: ffff99c9ba6c5dc0 RCX: 0000000000000049
[ 2.780490] RDX: 0000000000000000 RSI: ffff99c9ba6c5dc0 RDI: ffff99c9baac6e40
[ 2.781087] RBP: 0000000000000001 R08: 0000000000000202 R09: 0000000000000000
[ 2.781739] R10: 0000000000000001 R11: 0000000000000000 R12: ffff99c9baac6e40
[ 2.782400] R13: ffff99c9bc509c40 R14: ffff99c9ba6c5dc0 R15: ffff99c9baac6e40
[ 2.783000] FS: 00007f410fff3840(0000) GS:ffff99c9bfc80000(0000) knlGS:0000000000000000
[ 2.783630] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2.784059] CR2: 00007f410df0d000 CR3: 000000007a8f4000 CR4: 00000000000006e0
[ 2.784606] Call Trace:
[ 2.784807] __schedule+0x20e/0x6d0
[ 2.785083] schedule+0x23/0x80
[ 2.785331] schedule_hrtimeout_range_clock+0x158/0x170
[ 2.785744] ? ep_scan_ready_list.constprop.16+0x1de/0x1e0
[ 2.786178] ? file_has_perm+0x57/0x90
[ 2.786472] ep_poll+0x26f/0x370
[ 2.786730] ? wake_up_q+0x70/0x70
[ 2.786998] SyS_epoll_wait+0xb8/0xd0
[ 2.787285] do_syscall_64+0x5c/0x110
[ 2.787575] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 2.787967] RIP: 0033:0x7f410f904be3
[ 2.788245] RSP: 002b:00007ffff3e65c58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
[ 2.788828] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00007f410f904be3
[ 2.789376] RDX: 000000000000000f RSI: 00007ffff3e65c60 RDI: 0000000000000007
[ 2.789919] RBP: 00007ffff3e65e40 R08: 00000000000216c7 R09: 00000000ff9746cd
[ 2.790466] R10: 00000000ffffffff R11: 0000000000000246 R12: 000055b4dd2270d0
[ 2.791009] R13: 000055b4dd2270f0 R14: 000055b4dd2270b0 R15: 00007ffff3e65c60
[ 2.791518] Code: 8b 45 00 49 8b 7d 08 49 83 c5 18 31 d2 31 f6 ff d0 49 8b 45 00 48 85 c0 75 e9 eb b1 b9 49 00 00 00 b8 01 00 00 00 ba 00 00 00 00 <0f> 30 e9 68 fd ff ff 9c 58 0f 1f 44 00 00 48 89 c5 fa 66 0f 1f
[ 2.792931] RIP: switch_mm_irqs_off+0x2f1/0x3c0 RSP: ffffac6f0053bd60
[ 2.793518] ---[ end trace eb29cfddc2907c66 ]---
Thanks,
//richard
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