Re: Perf: WARNING: arch/x86/entry/common.c:624 idtentry_exit_cond_rcu+0x92/0xc0

[Naresh Kamboju]

I have reported this warning on linux-next and now it is happening on
linux mainline tree.
May I know , are we missing a fix patch on linus 's tree ?

- Naresh
---
While running selftest x86 single_step_syscall_32 on
i386 kernel linux 5.8.0-rc3 kernel warning noticed.

steps to reproduce:
--------------------------
perf test
and
cd /opt/kselftests/default-in-kernel/x86
./single_step_syscall_32

crash dump,
[ 1324.774385] kselftest: Running tests in x86
[ 1324.830187] ------------[ cut here ]------------
[ 1324.834820] IRQs not disabled as expected
[ 1324.838838] WARNING: CPU: 2 PID: 5365 at
/usr/src/kernel/arch/x86/entry/common.c:645
idtentry_exit_cond_rcu+0x92/0xc0
[ 1324.849448] Modules linked in: test_sysctl nf_tables act_mirred
cls_u32 sch_netem sch_ingress mpls_iptunnel mpls_router sch_etf sch_fq
sit x86_pkg_temp_thermal fuse [last unloaded: test_user_copy]
[ 1324.866909] CPU: 2 PID: 5365 Comm: single_step_sys Not tainted 5.8.0-rc3 #1
[ 1324.873866] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 1324.881340] EIP: idtentry_exit_cond_rcu+0x92/0xc0
[ 1324.886045] Code: 8b 89 d8 05 00 00 85 c9 74 ae 80 3d 3f 1d f8 de
00 75 a5 68 3c 6f c5 de 89 55 f8 89 45 fc c6 05 3f 1d f8 de 01 e8 7e
17 23 ff <0f> 0b 58 8b 55 f8 8b 45 fc eb 83 8d 76 00 e8 5b fd ff ff c9
c3 89
[ 1324.904790] EAX: 0000001d EBX: 00000000 ECX: 00000027 EDX: f594c14c
[ 1324.911055] ESI: f1da3fb4 EDI: ffff4ff0 EBP: f1da3f8c ESP: f1da3f80
[ 1324.917312] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010096
[ 1324.924090] CR0: 80050033 CR2: 0883a16c CR3: 26c06000 CR4: 003406d0
[ 1324.930347] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 1324.936622] DR6: fffe0ff0 DR7: 00000400
[ 1324.940460] Call Trace:
[ 1324.942906]  exc_debug+0x84/0x1b0
[ 1324.946224]  ? exc_int3+0x1d0/0x1d0
[ 1324.949716]  handle_exception+0x145/0x145
[ 1324.953720] EIP: 0x8048900
[ 1324.956423] Code: Bad RIP value.
[ 1324.959646] EAX: 00000005 EBX: 00000000 ECX: bfe19f0c EDX: bfe19e8c
[ 1324.965903] ESI: b7e3a000 EDI: 00000000 EBP: bfe1a488 ESP: bfe19e7c
[ 1324.972161] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000282
[ 1324.978942] irq event stamp: 3694
[ 1324.982257] hardirqs last  enabled at (3693): [<de8bf6b9>]
idtentry_exit_user+0x39/0x60
[ 1324.990251] hardirqs last disabled at (3694): [<ddb6ea62>]
vprintk_emit+0x42/0x290
[ 1324.997814] softirqs last  enabled at (3688): [<ddab1d98>]
fpu__clear+0x78/0xd0
[ 1325.005110] softirqs last disabled at (3686): [<ddab1d41>]
fpu__clear+0x21/0xd0
[ 1325.012406] ---[ end trace d68e89e2115323e2 ]---
[ 1325.017075] ------------[ cut here ]------------
[ 1325.021688] IRQs not disabled as expected
[ 1325.025695] WARNING: CPU: 2 PID: 5365 at
/usr/src/kernel/arch/x86/entry/common.c:240
__prepare_exit_to_usermode+0x164/0x1b0
[ 1325.036811] Modules linked in: test_sysctl nf_tables act_mirred
cls_u32 sch_netem sch_ingress mpls_iptunnel mpls_router sch_etf sch_fq
sit x86_pkg_temp_thermal fuse [last unloaded: test_user_copy]
[ 1325.054258] CPU: 2 PID: 5365 Comm: single_step_sys Tainted: G
 W         5.8.0-rc3 #1
[ 1325.062624] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 1325.070099] EIP: __prepare_exit_to_usermode+0x164/0x1b0
[ 1325.075315] Code: d8 05 00 00 85 db 0f 84 08 ff ff ff 80 3d 40 1d
f8 de 00 0f 85 fb fe ff ff 68 3c 6f c5 de c6 05 40 1d f8 de 01 e8 7c
ee 0e 00 <0f> 0b 59 e9 e2 fe ff ff 8d 74 26 00 68 e4 6e c5 de e8 66 ee
0e 00
[ 1325.094053] EAX: 0000001d EBX: 00000001 ECX: 00000027 EDX: f594c14c
[ 1325.100309] ESI: f5766c00 EDI: f1da3fb4 EBP: f1da3f74 ESP: f1da3f64
[ 1325.106583] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010086
[ 1325.113378] CR0: 80050033 CR2: 0804d084 CR3: 26c06000 CR4: 003406d0
[ 1325.119637] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 1325.125902] DR6: fffe0ff0 DR7: 00000400
[ 1325.129731] Call Trace:
[ 1325.132179]  prepare_exit_to_usermode+0x8/0x30
[ 1325.136624]  idtentry_exit_cond_rcu+0xa5/0xc0
[ 1325.140983]  ? idtentry_exit_user+0x39/0x60
[ 1325.145168]  exc_debug+0x84/0x1b0
[ 1325.148480]  ? exc_int3+0x1d0/0x1d0
[ 1325.151970]  handle_exception+0x145/0x145
[ 1325.155973] EIP: 0x8048900
[ 1325.158677] Code: Bad RIP value.
[ 1325.161901] EAX: 00000005 EBX: 00000000 ECX: bfe19f0c EDX: bfe19e8c
[ 1325.168160] ESI: b7e3a000 EDI: 00000000 EBP: bfe1a488 ESP: bfe19e7c
[ 1325.174423] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000282
[ 1325.181205] irq event stamp: 3808
[ 1325.184520] hardirqs last  enabled at (3807): [<de8bf6b9>]
idtentry_exit_user+0x39/0x60
[ 1325.192512] hardirqs last disabled at (3808): [<ddb6ea62>]
vprintk_emit+0x42/0x290
[ 1325.200079] softirqs last  enabled at (3802): [<ddab1d98>]
fpu__clear+0x78/0xd0
[ 1325.207384] softirqs last disabled at (3800): [<ddab1d41>]
fpu__clear+0x21/0xd0
[ 1325.214688] ---[ end trace d68e89e2115323e3 ]---