[BUG] general protection fault in sysfs_do_create_link_sd

[BUG] general protection fault in sysfs_do_create_link_sd

[Farhad Alemi]

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/188-general-protection-fault-in-sysfs-do-create-link-sd/

  Oops: general protection fault, probably for non-canonical address
0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
  RIP: 0010:sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
  Call Trace:
   sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
   nfs_sysfs_link_rpc_client+0x3a3/0x590 fs/nfs/sysfs.c:343
   nfs_init_server fs/nfs/client.c:770 [inline]
   nfs_create_server+0x7e8/0x2110 fs/nfs/client.c:1155
   nfs3_create_server+0x1e/0x180 fs/nfs/nfs3client.c:56
   nfs_try_get_tree+0x1fa/0x11a0 fs/nfs/super.c:981
   vfs_get_tree+0x8f/0x290 fs/super.c:1754
   do_new_mount+0x341/0xd80 fs/namespace.c:3834

Our reproducer.c is available upon request.

Happy to test a patch if that would help.

Regards,

Re: [BUG] general protection fault in sysfs_do_create_link_sd

[Greg Kroah-Hartman]

On Fri, Aug 28, 2026 at 05:50:00AM +0000, Farhad Alemi wrote:
> 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/188-general-protection-fault-in-sysfs-do-create-link-sd/
> 
>   Oops: general protection fault, probably for non-canonical address
> 0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI
>   KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
>   RIP: 0010:sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
>   Call Trace:
>    sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
>    nfs_sysfs_link_rpc_client+0x3a3/0x590 fs/nfs/sysfs.c:343
>    nfs_init_server fs/nfs/client.c:770 [inline]
>    nfs_create_server+0x7e8/0x2110 fs/nfs/client.c:1155
>    nfs3_create_server+0x1e/0x180 fs/nfs/nfs3client.c:56
>    nfs_try_get_tree+0x1fa/0x11a0 fs/nfs/super.c:981
>    vfs_get_tree+0x8f/0x290 fs/super.c:1754
>    do_new_mount+0x341/0xd80 fs/namespace.c:3834
> 
> Our reproducer.c is available upon request.
> 
> Happy to test a patch if that would help.

Please stop sending random callbacks, instead send proper patches, as
this helps no one.

thanks,

greg k-h

Re: [BUG] general protection fault in sysfs_do_create_link_sd

[Greg Kroah-Hartman]

On Fri, Aug 28, 2026 at 05:50:00AM +0000, Farhad Alemi wrote:
> 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/188-general-protection-fault-in-sysfs-do-create-link-sd/
> 
>   Oops: general protection fault, probably for non-canonical address
> 0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI
>   KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
>   RIP: 0010:sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
>   Call Trace:
>    sysfs_do_create_link_sd+0x4b/0x110 fs/sysfs/symlink.c:35
>    nfs_sysfs_link_rpc_client+0x3a3/0x590 fs/nfs/sysfs.c:343
>    nfs_init_server fs/nfs/client.c:770 [inline]
>    nfs_create_server+0x7e8/0x2110 fs/nfs/client.c:1155
>    nfs3_create_server+0x1e/0x180 fs/nfs/nfs3client.c:56
>    nfs_try_get_tree+0x1fa/0x11a0 fs/nfs/super.c:981
>    vfs_get_tree+0x8f/0x290 fs/super.c:1754
>    do_new_mount+0x341/0xd80 fs/namespace.c:3834
> 
> Our reproducer.c is available upon request.
> 
> Happy to test a patch if that would help.

Again, please send patches.