Re: [BUG] general protection fault in security_path_post_mknod

Hi Paul,

Upon our run, the patched kernel (proposed patch applied on
28924df2a08f) no longer panics on the reproducer.

Thanks,

On Fri, Aug 28, 2026 at 11:48 AM Paul Moore [off-list ref] wrote:

On Fri, Aug 28, 2026 at 2:11 AM Farhad Alemi [off-list ref] wrote:

quoted

Hello,

As part of the kernel research at ASU's SEFCOM
lab, we hit the crash below. Crash reports can be found here:

  https://github.com/farhad-alemi/public_bug_reports/tree/main/178-general-protection-fault-in-security-path-post-mknod/

  Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:security_path_post_mknod+0x49/0x1e0 security/security.c:1430
  Call Trace:
   security_path_post_mknod+0x49/0x1e0 security/security.c:1430
   filename_mknodat+0x40e/0x660 fs/namei.c:5172
   __do_sys_mknod fs/namei.c:5207 [inline]
   __se_sys_mknod+0x3a/0x150 fs/namei.c:5204
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x146/0x480 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

Our reproducer.c is available upon request.

Happy to test a patch if that would help.

Hi Farhad, thanks for the report.  Do you think you can diagnose the
problem and submit a patch?  Bug reports are always welcome, but as
you may have noticed, we have plenty of those at the moment.  People
willing to not only identify problems but fix them too is something we
are running a bit short on at the moment ;)

--
paul-moore.com