Re: [x86/pgtable] d1ec551f87: BUG:Bad_page_map_in_process

[David Hildenbrand]

On 19.04.22 09:59, kernel test robot wrote:
> 
> 
> Greeting,
> 
> FYI, we noticed the following commit (built with clang-15):
> 
> commit: d1ec551f874e1663bfe76b994c0010a4566cf936 ("x86/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE")
> https://github.com/hnaz/linux-mm master
> 
> in testcase: trinity
> version: trinity-static-i386-x86_64-1c734c75-1_2020-01-06
> with following parameters:
> 
> 	runtime: 300s
> 	group: group-01
> 
> test-description: Trinity is a linux system call fuzz tester.
> test-url: http://codemonkey.org.uk/projects/trinity/
> 
> 
> on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
> 
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 
> 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> 
> 
> [   40.201103][ T5099] BUG: Bad page map in process trinity-c7  pte:1713003a pmd:7ff71067
> [   40.201999][ T5099] addr:096e7000 vm_flags:00100073 anon_vma:bff0aa00 mapping:00000000 index:96e7
> [   40.202718][ T5099] file:(null) fault:0x0 mmap:0x0 readpage:0x0
> [   40.203229][ T5099] CPU: 0 PID: 5099 Comm: trinity-c7 Not tainted 5.18.0-rc2-mm1-00053-gd1ec551f874e #1
> [   40.203952][ T5099] Call Trace:
> [ 40.204195][ T5099] ? dump_stack_lvl (??:?) 
> [ 40.204581][ T5099] ? dump_stack (??:?) 
> [ 40.204970][ T5099] ? print_bad_pte (memory.c:?) 
> [ 40.205384][ T5099] ? unmap_page_range (??:?) 
> [ 40.205843][ T5099] ? unmap_single_vma (memory.c:?) 
> [ 40.206271][ T5099] ? unmap_vmas (??:?) 
> [ 40.206647][ T5099] ? exit_mmap (??:?) 
> [ 40.207032][ T5099] ? __mmput (fork.c:?) 
> [ 40.207405][ T5099] ? mmput (??:?) 
> [ 40.207751][ T5099] ? exit_mm (exit.c:?) 
> [ 40.208121][ T5099] ? do_exit (??:?) 
> [ 40.208497][ T5099] ? do_group_exit (??:?) 
> [ 40.208905][ T5099] ? trace_hardirqs_on (??:?) 
> [ 40.209345][ T5099] ? get_signal (??:?) 
> [ 40.209750][ T5099] ? arch_do_signal_or_restart (??:?) 
> [ 40.210287][ T5099] ? exit_to_user_mode_loop (common.c:?) 
> [ 40.210778][ T5099] ? exit_to_user_mode_prepare (common.c:?) 
> [ 40.211302][ T5099] ? syscall_exit_to_user_mode (??:?) 
> [ 40.211808][ T5099] ? ret_from_fork (??:?) 
> [   40.212268][ T5099] Disabling lock debugging due to kernel taint
> [   40.231123][ T5097] BUG: Bad page map in process trinity-c5  pte:171e0a3e pmd:0a8d3067
> [   40.231770][ T5099] BUG: Bad page map in process trinity-c7  pte:1713023a pmd:7ff71067
> [   40.231883][ T5097] addr:36ed5000 vm_flags:000000fb anon_vma:00000000 mapping:485d0d80 index:1
> [   40.232611][ T5099] addr:096e8000 vm_flags:00100073 anon_vma:bff0ab18 mapping:00000000 index:96e8
> [   40.233429][ T5097] file:dev/zero fault:shmem_fault mmap:shmem_mmap readpage:0x0
> [   40.234271][ T5099] file:(null) fault:0x0 mmap:0x0 readpage:0x0
> [   40.234971][ T5097] CPU: 1 PID: 5097 Comm: trinity-c5 Tainted: G    B             5.18.0-rc2-mm1-00053-gd1ec551f874e #1
> [   40.236510][ T5097] Call Trace:

This is 32bit (i386) I assume. I wonder if something about the 32bit swp
layout is special and we have to restrict it to 64bit here.

-- 
Thanks,

David / dhildenb