Re: list_del corruption / unhash_ol_stateid()

[Andrew W Elble <aweits@rit.edu>]

> [12492.273425] WARNING: CPU: 0 PID: 32238 at fs/nfsd/nfs4state.c:3937
> nfsd4_process_open2+0x120d/0x1230 [nfsd]()

3931          fl = nfs4_alloc_init_lease(fp, NFS4_OPEN_DELEGATE_READ);
3932          if (!fl)
3933                  return -ENOMEM;
3934          filp = find_readable_file(fp);
3935          if (!filp) {
3936                  /* We should always have a readable file here */
3937                  WARN_ON_ONCE(1);
3938                  return -EBADF;
3939          }
          
We're at least leaking fl on return @3938 here? Can't yet speak to the
trigger from find_readable_file().

1007  static void unhash_ol_stateid(struct nfs4_ol_stateid *stp)
1008  {
1009          struct nfs4_file *fp = stp->st_stid.sc_file;
1010
1011          lockdep_assert_held(&stp->st_stateowner->so_client->cl_lock);
1012
1013          spin_lock(&fp->fi_lock);
1014          list_del(&stp->st_perfile);
1015          spin_unlock(&fp->fi_lock);
1016          list_del(&stp->st_perstateowner);
1017  }

The list_del corruption warning is triggered from here:

1014          list_del(&stp->st_perfile);

Actual crash looks like so:

PID: 32237  TASK: ffff881f391cdef0  CPU: 22  COMMAND: "nfsd"
 #0 [ffff881f48ed36f0] machine_kexec at ffffffff8105bf3b
 #1 [ffff881f48ed3760] crash_kexec at ffffffff81109b52
 #2 [ffff881f48ed3830] oops_end at ffffffff81019768
 #3 [ffff881f48ed3860] no_context at ffffffff8167e502
 #4 [ffff881f48ed38c0] __bad_area_nosemaphore at ffffffff8167e5ed
 #5 [ffff881f48ed3910] bad_area_nosemaphore at ffffffff8167e759
 #6 [ffff881f48ed3920] __do_page_fault at ffffffff810687e6
 #7 [ffff881f48ed3990] do_page_fault at ffffffff81068bb0
 #8 [ffff881f48ed39d0] page_fault at ffffffff8168d398
    [exception RIP: __kmalloc+150]
    RIP: ffffffff811dab66  RSP: ffff881f48ed3a88  RFLAGS: 00010286
    RAX: 0000000000000000  RBX: 000000000000000a  RCX: 00000000009f26fa
    RDX: 00000000009f26f9  RSI: 0000000000000000  RDI: ffffffff8124cfc0
    RBP: ffff881f48ed3ac8   R8: 000000000001ab00   R9: 0000000000000000
    R10: ffff881f48ed3918  R11: ffffffffa0852070  R12: 0000000000000050
    R13: 0000000000000068  R14: ffff881fff403900  R15: 00000000ffffffff
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #9 [ffff881f48ed3ad0] posix_acl_alloc at ffffffff8124cfc0
#10 [ffff881f48ed3af0] posix_acl_from_xattr at ffffffff8124da44
#11 [ffff881f48ed3b40] gfs2_get_acl at ffffffffa0852064 [gfs2]
#12 [ffff881f48ed3b70] get_acl at ffffffff8124d557
#13 [ffff881f48ed3b90] generic_permission at ffffffff811fb4a2
#14 [ffff881f48ed3bd0] gfs2_permission at ffffffffa086d98d [gfs2]
#15 [ffff881f48ed3c70] __inode_permission at ffffffff811fb572
#16 [ffff881f48ed3ca0] inode_permission at ffffffff811fb5e8
#17 [ffff881f48ed3cb0] nfsd_permission at ffffffffa05f6552 [nfsd]
#18 [ffff881f48ed3ce0] nfsd_access at ffffffffa05f77a8 [nfsd]
#19 [ffff881f48ed3d40] nfsd4_access at ffffffffa06022ec [nfsd]
#20 [ffff881f48ed3d50] nfsd4_proc_compound at ffffffffa0604147 [nfsd]
#21 [ffff881f48ed3db0] nfsd_dispatch at ffffffffa05efff3 [nfsd]
#22 [ffff881f48ed3df0] svc_process_common at ffffffffa019d483 [sunrpc]
#23 [ffff881f48ed3e60] svc_process at ffffffffa019d833 [sunrpc]
#24 [ffff881f48ed3e90] nfsd at ffffffffa05ef9ff [nfsd]
#25 [ffff881f48ed3ec0] kthread at ffffffff8109c8d8
#26 [ffff881f48ed3f50] ret_from_fork at ffffffff8168b7a2

Thanks,

Andy

-- 
Andrew W. Elble
aweits@discipline.rit.edu
Infrastructure Engineer, Communications Technical Lead
Rochester Institute of Technology
PGP: BFAD 8461 4CCF DC95 DA2C B0EB 965B 082E 863E C912