Messages in this thread | | | Date | Tue, 31 Mar 2009 08:07:34 -0500 | Subject | Re: [linux-cifs-client] consistent oops from request_key in 2.6.29 | From | Shirish Pargaonkar <> |
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On Tue, Mar 31, 2009 at 7:45 AM, Jeff Layton <jlayton@redhat.com> wrote: > I've started seeing a consistent oops in recent rawhide kernels when I > try to do CIFS mounts with krb5 auth: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 > IP: [<ffffffff8102bf4c>] __ticket_spin_trylock+0x4/0x21 > PGD 0 > Oops: 0000 [#1] SMP > last sysfs file: /sys/devices/pci0000:00/0000:00:04.0/local_cpus > CPU 1 > Modules linked in: nls_utf8 cifs sunrpc ipv6 dm_multipath uinput 8139too 8139cp i2c_piix4 mii i2c_core pcspkr ata_generic pata_acpi [last unloaded: freq_table] > Pid: 2255, comm: mount.cifs Tainted: G W 2.6.29-16.fc11.x86_64 #1 HVM domU > RIP: 0010:[<ffffffff8102bf4c>] [<ffffffff8102bf4c>] __ticket_spin_trylock+0x4/0x21 > RSP: 0018:ffff8800370ab9d0 EFLAGS: 00010096 > RAX: ffff88003d0d23c0 RBX: 0000000000000030 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000030 > RBP: ffff8800370ab9d0 R08: 0000000000000002 R09: 0000000000000001 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000030 > R13: 0000000000000292 R14: ffff880037088000 R15: ffffffff81597ad0 > FS: 00007fa0e7fe56f0(0000) GS:ffff88003ea4b320(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: 0000000000000030 CR3: 00000000370c7000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process mount.cifs (pid: 2255, threadinfo ffff8800370aa000, task ffff88003d0d23c0) > Stack: > ffff8800370ab9e8 ffffffff811a2af9 0000000000000048 ffff8800370aba28 > ffffffff81399014 ffffffff8119ce86 ffffffff8116470a 0000000000000000 > 0000000000000030 0000000000000028 ffffffffa01292a0 ffff8800370aba48 > Call Trace: > [<ffffffff811a2af9>] _raw_spin_trylock+0xd/0x2d > [<ffffffff81399014>] _spin_lock_irqsave+0x59/0x8b > [<ffffffff8119ce86>] ? __down_write_trylock+0x16/0x4f > [<ffffffff8116470a>] ? request_key_and_link+0x220/0x3d5 > [<ffffffff8119ce86>] __down_write_trylock+0x16/0x4f > [<ffffffff81397a9c>] down_write+0x54/0x7f > [<ffffffff8116470a>] ? request_key_and_link+0x220/0x3d5 > [<ffffffff8116470a>] request_key_and_link+0x220/0x3d5 > [<ffffffff8119ec8d>] ? vsnprintf+0x2e7/0x4ed > [<ffffffff81164992>] request_key+0x41/0x72 > [<ffffffffa010f8e5>] cifs_get_spnego_key+0x189/0x1b4 [cifs] > [<ffffffffa010e4a0>] CIFS_SessSetup+0x442/0xb1e [cifs] > [<ffffffffa00f91c9>] cifs_setup_session+0x119/0xb61 [cifs] > [<ffffffff81398cc6>] ? _spin_unlock_irqrestore+0x48/0x58 > [<ffffffff81070acd>] ? trace_hardirqs_on+0xd/0xf > [<ffffffffa00fd5b6>] cifs_mount+0x17a7/0x1f2b [cifs] > [<ffffffff810dd173>] ? __kmalloc+0x10b/0x149 > [<ffffffffa00ee8ab>] cifs_get_sb+0x110/0x26a [cifs] > [<ffffffff810e71a9>] vfs_kern_mount+0xa3/0x13c > [<ffffffff810e72aa>] do_kern_mount+0x4d/0xe8 > [<ffffffff810fbe0b>] do_mount+0x744/0x790 > [<ffffffff811a2ed2>] ? _raw_spin_lock+0x65/0x111 > [<ffffffff810fbee9>] sys_mount+0x92/0xd5 > [<ffffffff8101133a>] system_call_fastpath+0x16/0x1b > Code: 1b fb ff ff c9 c3 90 55 b8 00 00 01 00 48 89 e5 f0 0f c1 07 0f b7 d0 c1 e8 10 39 c2 74 07 f3 90 0f b7 17 eb f5 c9 c3 55 48 89 e5 <8b> 07 89 c2 c1 c0 10 39 c2 8d 90 00 00 01 00 75 04 f0 0f b1 17 > RIP [<ffffffff8102bf4c>] __ticket_spin_trylock+0x4/0x21 > RSP <ffff8800370ab9d0> > CR2: 0000000000000030 > ---[ end trace cee083cffbca031b ]--- > > > ...we call request_key from CIFS which calls request_key_and_link > with a NULL dest_keyring. Eventually this calls construct_alloc_key > with the NULL dest_keyring. The following patch seems to have changed > it so that it's no longer safe to call construct_alloc_key this way: > > commit 8bbf4976b59fc9fc2861e79cab7beb3f6d647640 > Author: David Howells <dhowells@redhat.com> > Date: Fri Nov 14 10:39:14 2008 +1100 > > KEYS: Alter use of key instantiation link-to-keyring argument > > > ...but request_key was never fixed so that it doesn't do this. It's > unclear to me what the correct fix is. Do we need to put the checks for > a NULL dest_keyring back into construct_alloc_key or fix request_key > to call request_key_and_link with a dest_keyring? > > Thanks, > -- > Jeff Layton <jlayton@redhat.com> > _______________________________________________ > linux-cifs-client mailing list > linux-cifs-client@lists.samba.org > https://lists.samba.org/mailman/listinfo/linux-cifs-client >
I have see that earlier too. This is the comment from David during that converstaion.
"Assuming:
printk("%s,%s,%p,%zu,%p,%p,%lx\n", type->name, description, callout_info, callout_len, aux, dest_keyring, flags);
produced:
> dns_resolver,cifstest8.,ffffffffa03323a9,0,(null),(null),0
then I'd say that the oops is because dest_keyring is NULL.
Let me think about why this is. "
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