>From 07a0eeb62a7bedec3f3312aff24ef62fbb36d820 Mon Sep 17 00:00:00 2001
From: majianpeng <majianpeng@xxxxxxxxx>
Date: Sun, 26 Feb 2012 20:43:05 +0800
Subject: [PATCH] md:When opened /proc/mdstat, increase the refcount of
md-mod.ko
If md configured module, polled /proc/mdstat and removed the md-mod
can incur oops problem.
Reproduce this bug by following step:
1:configure md is module and insmod
2:poll(/proc/mdstat,timeout)
3:remove md-mod.ko
4:oops occur
[ 343.764057] BUG: unable to handle kernel paging request at
ffffffffa007f9e0
[ 343.764101] IP: [<ffffffff8155578c>] _raw_spin_lock_irqsave+0xc/0x30
[ 343.764133] PGD 1807067 PUD 180b063 PMD b7b72067 PTE 0
[ 343.764167] Oops: 0002 [#1] SMP
[ 343.764190] CPU 3
[ 343.764205] Modules linked in: ext4 jbd2 crc16 async_pq async_xor xor
async_memcpy async_raid6_recov raid6_pq async_tx sata_sil e1000e mvsas
libsas scsi_transport_sas [last unloaded: md_mod]
[ 343.764304]
[ 343.764312] Pid: 5454, comm: udisks-daemon Not tainted 3.3.0-rc4+ #13
To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M.
[ 343.764366] RIP: 0010:[<ffffffff8155578c>] [<ffffffff8155578c>]
_raw_spin_lock_irqsave+0xc/0x30
[ 343.764403] RSP: 0018:ffff8800a514bab8 EFLAGS: 00010082
[ 343.764423] RAX: 0000000000000282 RBX: ffffffffa007f9e0 RCX:
ffff8800ba0051a8
[ 343.764448] RDX: 0000000000000100 RSI: ffff8800a514bc48 RDI:
ffffffffa007f9e0
[ 343.764473] RBP: ffff8800a514bab8 R08: ffff8800a9bdb630 R09:
0000000000000001
[ 343.764499] R10: 0000000000000000 R11: 0000000000000000 R12:
ffff8800a514bc48
[ 343.764524] R13: ffff8800a514bb88 R14: ffff8800a514be2c R15:
0000000000000000
[ 343.764551] FS: 00007fec6a4567c0(0000) GS:ffff8800bdb80000(0000)
knlGS:0000000000000000
[ 343.764582] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 343.764603] CR2: ffffffffa007f9e0 CR3: 00000000a50f5000 CR4:
00000000000406e0
[ 343.764628] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 343.764653] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000400
[ 343.764679] Process udisks-daemon (pid: 5454, threadinfo
ffff8800a514a000, task ffff8800b7c41d80)
[ 343.764710] Stack:
[ 343.764719] ffff8800a514bad8 ffffffff81054ceb 0000000000000003
ffff8800a514bc38
[ 343.764756] ffff8800a514bb28 ffffffff8112e216 ffff8800a514baf8
0000000000000000
[ 343.764794] ffff8800a514bb28 000000000128ed20 ffff8800a514bef8
0000000000000001
[ 343.764830] Call Trace:
[ 343.764842] [<ffffffff81054ceb>] remove_wait_queue+0x1b/0x60
[ 343.764864] [<ffffffff8112e216>] poll_freewait+0x46/0xd0
[ 343.764884] [<ffffffff8112f6e6>] do_sys_poll+0x416/0x500
[ 343.764905] [<ffffffff8112e2a0>] ? poll_freewait+0xd0/0xd0
[ 343.764926] [<ffffffff8112e390>] ? __pollwait+0xf0/0xf0
[ 343.764953] [<ffffffff8112e390>] ? __pollwait+0xf0/0xf0
[ 343.764979] [<ffffffff8112e390>] ? __pollwait+0xf0/0xf0
[ 343.765002] [<ffffffff8112e390>] ? __pollwait+0xf0/0xf0
[ 343.765002] [<ffffffff8112e390>] ? __pollwait+0xf0/0xf0
[ 343.765002] [<ffffffff8143aec6>] ? verify_iovec+0x56/0xd0
[ 343.765002] [<ffffffff8142eb76>] ? __sys_sendmsg+0x376/0x380
[ 343.765156] [<ffffffff810f7459>] ? handle_mm_fault+0x139/0x240
[ 343.765156] [<ffffffff81156b0a>] ? fsnotify+0x1ca/0x2b0
[ 343.765156] [<ffffffff811d0388>] ?
selinux_file_permission+0xe8/0x130
[ 343.765156] [<ffffffff81077408>] ? ktime_get_ts+0xa8/0xe0
[ 343.765156] [<ffffffff8112e58a>] ? poll_select_set_timeout+0x7a/0x90
[ 343.765156] [<ffffffff8112f896>] sys_poll+0x66/0x100
[ 343.765156] [<ffffffff8155d162>] system_call_fastpath+0x16/0x1b
[ 343.765156] Code: 8a 00 01 00 00 89 d0 f0 66 0f b1 0f 66 39 d0 0f 94
c0 0f b6 c0 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 9c 58 fa ba 00 01
00 00 <f0> 66 0f c1 17 0f b6 ce 38 d1 74 11 0f 1f 84 00 00 00 00 00 f3
[ 343.765156] RIP [<ffffffff8155578c>] _raw_spin_lock_irqsave+0xc/0x30
[ 343.765156] RSP <ffff8800a514bab8>
[ 343.765156] CR2: ffffffffa007f9e0
[ 343.791890] ---[ end trace 10ed0211ce0a5736 ]---
Signed-off-by: majianpeng <majianpeng@xxxxxxxxx>
---
drivers/md/md.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ce88755..105c7f9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6859,9 +6859,15 @@ static int md_seq_open(struct inode *inode, struct file *file)
seq = file->private_data;
seq->poll_event = atomic_read(&md_event_count);
+ __module_get(THIS_MODULE);
return error;
}
+static int md_seq_release(struct inode *inode, struct file *file)
+{
+ module_put(THIS_MODULE);
+ return seq_release_private(inode, file);
+}
static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
{
struct seq_file *seq = filp->private_data;
@@ -6882,7 +6888,7 @@ static const struct file_operations md_seq_fops = {
.open = md_seq_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release_private,
+ .release = md_seq_release,
.poll = mdstat_poll,
};
--
1.7.5.4
--------------
majianpeng
2012-02-26
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