| Summary: | Warning messages when using fscache with cifs | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Sachin Prabhu <sprabhu> |
| Component: | kernel | Assignee: | Sachin Prabhu <sprabhu> |
| Status: | CLOSED UPSTREAM | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | rawhide | CC: | dhowells, gansalmon, itamar, jlayton, jonathan, kernel-maint, madhu.chinakonda, marcelo.barbosa, skottler |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2014-01-13 20:05:32 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
|
Description
Sachin Prabhu
2013-09-09 10:12:12 UTC
I have narrowed down the cause to 0 byte files. To reproduce: 1) Mount the cifs share with the fsc mount option. 2) Cat a 0 byte file. This file can be created by a simple touch command to create a new file. If you continue to cat the file, the machine hangs after 4-5 attempts with the following message ---[ end trace 99afa34f9aad29b6 ]--- note: kworker/u8:0[6] exited with preempt_count 2 BUG: unable to handle kernel paging request at ffffffffffffff98 IP: [<ffffffff810a2c80>] kthread_data+0x10/0x20 PGD 1c0f067 PUD 1c11067 PMD 0 Oops: 0000 [#2] SMP Modules linked in: arc4 md4 nls_utf8 cifs dns_resolver nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_nat nf_nat_ipv6 ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables cachefiles fscache microcode serio_raw virtio_balloon virtio_net i2c_piix4 cirrus drm_kms_helper ttm drm virtio_blk i2c_core ata_generic pata_acpi CPU: 1 PID: 6 Comm: kworker/u8:0 Tainted: G D W 3.12.0-0.rc0.git11.1.fc21.x86_64 #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007 task: ffff88003d378000 ti: ffff88003d376000 task.ti: ffff88003d376000 RIP: 0010:[<ffffffff810a2c80>] [<ffffffff810a2c80>] kthread_data+0x10/0x20 RSP: 0018:ffff88003d377828 EFLAGS: 00010002 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 000000000000000d RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88003d378000 RBP: ffff88003d377828 R08: ffff88003d378090 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88003e1d5240 R13: 0000000000000001 R14: ffff88003d3774d8 R15: 0000000000000020 FS: 0000000000000000(0000) GS:ffff88003e000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000028 CR3: 000000002ee6a000 CR4: 00000000000006e0 Stack: ffff88003d377840 ffffffff8109a421 ffff88003d378000 ffff88003d3778a0 ffffffff8173e06a 00000000001d5240 ffff88003d377fd8 ffff88003d377fd8 00000000001d5240 ffff88003d378000 ffff88003d378730 ffff88003d3774d8 Call Trace: [<ffffffff8109a421>] wq_worker_sleeping+0x11/0x90 [<ffffffff8173e06a>] __schedule+0x63a/0x930 [<ffffffff8173e389>] schedule+0x29/0x70 [<ffffffff81079b80>] do_exit+0x7b0/0xcd0 [<ffffffff81742302>] oops_end+0xa2/0xe0 [<ffffffff81731e87>] no_context+0x268/0x275 [<ffffffff81731f12>] __bad_area_nosemaphore+0x7e/0x1d7 [<ffffffff8173207e>] bad_area_nosemaphore+0x13/0x15 [<ffffffff817451be>] __do_page_fault+0x23e/0x5a0 [<ffffffff811348f7>] ? rcu_irq_exit+0x77/0xc0 [<ffffffff817413b3>] ? retint_restore_args+0x13/0x13 [<ffffffff8137ea0d>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff8174552e>] do_page_fault+0xe/0x10 [<ffffffff81741688>] page_fault+0x28/0x30 [<ffffffffa00e2b6b>] ? __cachefiles_printk_object+0xfb/0x171 [cachefiles] [<ffffffffa00e2c3c>] cachefiles_printk_object+0x5b/0x41f [cachefiles] [<ffffffffa00e0551>] cachefiles_walk_to_object+0x871/0x880 [cachefiles] [<ffffffff810b99cd>] ? sched_clock_local+0x1d/0x80 [<ffffffff810e57bd>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff810b9c9f>] ? local_clock+0x5f/0x70 [<ffffffff810aa152>] ? creds_are_invalid.part.8+0x12/0x50 [<ffffffffa00deab4>] cachefiles_lookup_object+0x54/0x100 [cachefiles] [<ffffffffa0125275>] fscache_look_up_object+0xd5/0x1f0 [fscache] [<ffffffffa012550c>] fscache_object_work_func+0xbc/0x230 [fscache] [<ffffffff81098f01>] process_one_work+0x211/0x6e0 [<ffffffff81098e95>] ? process_one_work+0x1a5/0x6e0 [<ffffffff810994ed>] worker_thread+0x11d/0x3a0 [<ffffffff810993d0>] ? process_one_work+0x6e0/0x6e0 [<ffffffff810a22fd>] kthread+0xed/0x100 [<ffffffff810a2210>] ? insert_kthread_work+0x80/0x80 [<ffffffff8174a52c>] ret_from_fork+0x7c/0xb0 [<ffffffff810a2210>] ? insert_kthread_work+0x80/0x80 Code: 00 48 89 e5 5d 48 8b 40 88 48 c1 e8 02 83 e0 01 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8b 87 b8 04 00 00 55 48 89 e5 <48> 8b 40 98 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RIP [<ffffffff810a2c80>] kthread_data+0x10/0x20 RSP <ffff88003d377828> CR2: ffffffffffffff98 ---[ end trace 99afa34f9aad29b7 ]--- Fixing recursive fault but reboot is needed! To recreate the problem:
1) Enable fscache using the 'fsc' mount option.
2) This particular code path is hit on files having the read oplock.
3) Touch a new file and then subsequently cat it. You may need to do this a few times. I used the following command to reproduce the issue.
# for i in {1..30}; do touch t$i; done
# cat *
You may need to run cat a few times before you hit the problem.
Committed upstream: 466bd31bbda9e1dd2ace1d72c8de5045bf6f3bf6 http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=466bd31bbda9e1dd2ace1d72c8de5045bf6f3bf6 |