Re: linux-next: x86: Unalbe to run x32 processes on the x86_64 kernel

[Andrei Vagin]

Here is my bisect log:
[avagin@laptop linux-next]$ git bisect log
# bad: [f921b263d9602fb7873710c2df70671f2ffcf658] Add linux-next
specific files for 20170320
# good: [4495c08e84729385774601b5146d51d9e5849f81] Linux 4.11-rc2
git bisect start 'HEAD' 'v4.11-rc2'
# good: [adeec71e7b8a11ff44103cfa4e1c6002c27ae9ac] Merge
remote-tracking branch 'drm/drm-next'
git bisect good adeec71e7b8a11ff44103cfa4e1c6002c27ae9ac
# bad: [e5b1cee1bb9d8a66b28d64db9d8250ae2b0803d2] Merge
remote-tracking branch 'tty/tty-next'
git bisect bad e5b1cee1bb9d8a66b28d64db9d8250ae2b0803d2
# good: [81cde6aecf21113c6bc65bc944587db4cbd3f64d] Merge
remote-tracking branch 'mmc/next'
git bisect good 81cde6aecf21113c6bc65bc944587db4cbd3f64d
# bad: [69d76288005784205678520826a74c28e49a1703] Merge
remote-tracking branch 'tip/auto-latest'
git bisect bad 69d76288005784205678520826a74c28e49a1703
# good: [6d32edf2be6c4e0f08b102e2d3227278ebb477c9] Merge
remote-tracking branch 'spi/for-next'
git bisect good 6d32edf2be6c4e0f08b102e2d3227278ebb477c9
# good: [61f63e383784bd0ab6529cfc95ddc59c713afcc9] Merge tag
'perf-core-for-mingo-4.12-20170316' of
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into
perf/core
git bisect good 61f63e383784bd0ab6529cfc95ddc59c713afcc9
# good: [3069c5a046ec92dc552194686c95e27c8c9e919d] Merge branch 'x86/asm'
git bisect good 3069c5a046ec92dc552194686c95e27c8c9e919d
# bad: [5b804ec2fd3272385ba7530c3a67d7402fb6d8a0] Merge branch 'x86/mm'
git bisect bad 5b804ec2fd3272385ba7530c3a67d7402fb6d8a0
# good: [06c830a48346643e195801460dfe16d96ba4dff5] x86/power: Add
5-level paging support
git bisect good 06c830a48346643e195801460dfe16d96ba4dff5
# good: [2bbbd194fdca01f694e2ca3fb447a1acf9d19f76] Merge branch 'x86/cpu'
git bisect good 2bbbd194fdca01f694e2ca3fb447a1acf9d19f76
# good: [69218e47994da614e7af600bf06887750ab6657a] x86: Remap GDT
tables in the fixmap section
git bisect good 69218e47994da614e7af600bf06887750ab6657a
# bad: [74c8ce958dbf0b64f198becb5d8aa93afb967438] Merge branch 'linus'
into x86/mm, to pick up a bugfix
git bisect bad 74c8ce958dbf0b64f198becb5d8aa93afb967438
# bad: [45fc8757d1d2128e342b4e7ef39adedf7752faac] x86: Make the GDT
remapping read-only on 64-bit
git bisect bad 45fc8757d1d2128e342b4e7ef39adedf7752faac
# first bad commit: [45fc8757d1d2128e342b4e7ef39adedf7752faac] x86:
Make the GDT remapping read-only on 64-bit

On Mon, Mar 20, 2017 at 4:57 PM, Andrei Vagin <avagin@xxxxxxxxx> wrote:
> Hello,
>
> We run CRIU tests on linux-next. And today we found that when we start
> x32 processes, a kernel bug is triggered:
>
> [root@fc24 ~]# uname -a
> Linux fc24 4.11.0-rc2-next-20170320 #159 SMP Mon Mar 20 16:53:58 PDT
> 2017 x86_64 x86_64 x86_64 GNU/Linux
> [root@fc24 ~]# cat t.c
> int main()
> {
> return 0;
> }
> [root@fc24 ~]# gcc -m32 t.c
> [root@fc24 ~]# ./a.out
> Killed
> [root@fc24 ~]# dmesg
> [   90.033310] BUG: unable to handle kernel paging request at ffffffffff576060
> [   90.034008] IP: 0xf76fa9f4
> [   90.034008] PGD 13de1e067
> [   90.034008] P4D 13de1e067
> [   90.034008] PUD 13de20067
> [   90.034008] PMD 13de21067
> [   90.034008] PTE 800000013fd09161
>
> [   90.034008] Oops: 0003 [#1] SMP
> [   90.034008] Modules linked in:
> [   90.034008] CPU: 1 PID: 475 Comm: a.out Not tainted
> 4.11.0-rc2-next-20170320 #159
> [   90.034008] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS 1.9.3-1.fc25 04/01/2014
> [   90.034008] task: ffff9d11efdca700 task.stack: ffffb0ccc0d4c000
> [   90.034008] RIP: 0023:0xf76fa9f4
> [   90.034008] RSP: 002b:00000000ffafc860 EFLAGS: 00010246
> [   90.034008] RAX: 0000000000000063 RBX: 00000000ffafc860 RCX: 0000000008aea440
> [   90.034008] RDX: 00000000f7515700 RSI: 00000000f771dfcc RDI: 0000000000000040
> [   90.034008] RBP: 00000000ffafc928 R08: 0000000000000000 R09: 0000000000000000
> [   90.034008] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> [   90.034008] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [   90.034008] FS:  0000000000000000(0000) GS:ffff9d11ffd00000(0000)
> knlGS:0000000000000000
> [   90.034008] CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
> [   90.034008] CR2: ffffffffff576060 CR3: 000000012fd8d000 CR4: 00000000003406e0
> [   90.034008] RIP: 0xf76fa9f4 RSP: 00000000ffafc860
> [   90.034008] CR2: ffffffffff576060
> [   90.034008] ---[ end trace 3c9a8bbd0d11f377 ]---
> [   90.034008] BUG: sleeping function called from invalid context at
> ./include/linux/percpu-rwsem.h:33
> [   90.034008] in_atomic(): 0, irqs_disabled(): 1, pid: 475, name: a.out
> [   90.034008] INFO: lockdep is turned off.
> [   90.034008] irq event stamp: 2014
> [   90.034008] hardirqs last  enabled at (2013): [<ffffffffb98dc39d>]
> entry_INT80_compat+0x3d/0x50
> [   90.034008] hardirqs last disabled at (2014): [<ffffffffb98dc03c>]
> error_entry+0x6c/0xd0
> [   90.034008] softirqs last  enabled at (1666): [<ffffffffb98df7cd>]
> __do_softirq+0x38d/0x4c3
> [   90.034008] softirqs last disabled at (1657): [<ffffffffb90947b7>]
> irq_exit+0xf7/0x100
> [   90.034008] CPU: 1 PID: 475 Comm: a.out Tainted: G      D
> 4.11.0-rc2-next-20170320 #159
> [   90.034008] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS 1.9.3-1.fc25 04/01/2014
> [   90.034008] Call Trace:
> [   90.034008]  dump_stack+0x86/0xc1
> [   90.034008]  ___might_sleep+0x17d/0x250
> [   90.034008]  __might_sleep+0x4a/0x80
> [   90.034008]  exit_signals+0x33/0x250
> [   90.034008]  ? blocking_notifier_call_chain+0x16/0x20
> [   90.034008]  do_exit+0xbb/0xc60
> [   90.034008]  ? trace_do_page_fault+0x58/0x2a0
> [   90.034008]  rewind_stack_do_exit+0x17/0x20
> [   90.034008] RIP: 0023:0xf76fa9f4
> [   90.034008] RSP: 002b:00000000ffafc860 EFLAGS: 00010246
> [   90.034008] RAX: 0000000000000063 RBX: 00000000ffafc860 RCX: 0000000008aea440
> [   90.034008] RDX: 00000000f7515700 RSI: 00000000f771dfcc RDI: 0000000000000040
> [   90.034008] RBP: 00000000ffafc928 R08: 0000000000000000 R09: 0000000000000000
> [   90.034008] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> [   90.034008] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>
> Thanks,
> Andrei