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authorRobert Richter <robert.richter@amd.com>2011-10-07 16:31:46 +0200
committerRobert Richter <robert.richter@amd.com>2011-11-04 15:04:33 +0100
commit87121ca504fd1d963a66b3fb0c72054b0fd9a177 (patch)
tree789b9c8a7ea7b92d5359aa59653dd394bdec3710 /drivers/oprofile
parent4167ab90ee6a2c029855db53d1631c84a213f3d1 (diff)
downloadkernel-87121ca504fd1d963a66b3fb0c72054b0fd9a177.tar.gz
oprofile: Fix crash when unloading module (hr timer mode)
Oprofile may crash in a KVM guest while unlaoding modules. This happens if oprofile_arch_init() fails and oprofile switches to the hr timer mode as a fallback. In this case oprofile_arch_exit() is called, but it never was initialized properly which causes the crash. This patch fixes this. oprofile: using timer interrupt. BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58 PGD 41da3f067 PUD 41d80e067 PMD 0 Oops: 0002 [#1] PREEMPT SMP CPU 5 Modules linked in: oprofile(-) Pid: 2382, comm: modprobe Not tainted 3.1.0-rc7-00018-g709a39d #18 Advanced Micro Device Anaheim/Anaheim RIP: 0010:[<ffffffff8123c226>] [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58 RSP: 0018:ffff88041de1de98 EFLAGS: 00010296 RAX: 0000000000000000 RBX: ffffffffa00060e0 RCX: dead000000200200 RDX: 0000000000000000 RSI: dead000000100100 RDI: ffffffff8178c620 RBP: ffff88041de1dea8 R08: 0000000000000001 R09: 0000000000000082 R10: 0000000000000000 R11: ffff88041de1dde8 R12: 0000000000000080 R13: fffffffffffffff5 R14: 0000000000000001 R15: 0000000000610210 FS: 00007f9ae5bef700(0000) GS:ffff88042fd40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000008 CR3: 000000041ca44000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process modprobe (pid: 2382, threadinfo ffff88041de1c000, task ffff88042db6d040) Stack: ffff88041de1deb8 ffffffffa0006770 ffff88041de1deb8 ffffffffa000251e ffff88041de1dec8 ffffffffa00022c2 ffff88041de1ded8 ffffffffa0004993 ffff88041de1df78 ffffffff81073115 656c69666f72706f 0000000000610200 Call Trace: [<ffffffffa000251e>] op_nmi_exit+0x15/0x17 [oprofile] [<ffffffffa00022c2>] oprofile_arch_exit+0xe/0x10 [oprofile] [<ffffffffa0004993>] oprofile_exit+0x13/0x15 [oprofile] [<ffffffff81073115>] sys_delete_module+0x1c3/0x22f [<ffffffff811bf09e>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff8148070b>] system_call_fastpath+0x16/0x1b Code: 20 c6 78 81 e8 c5 cc 23 00 48 8b 13 48 8b 43 08 48 be 00 01 10 00 00 00 ad de 48 b9 00 02 20 00 00 00 ad de 48 c7 c7 20 c6 78 81 89 42 08 48 89 10 48 89 33 48 89 4b 08 e8 a6 c0 23 00 5a 5b RIP [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58 RSP <ffff88041de1de98> CR2: 0000000000000008 ---[ end trace 06d4e95b6aa3b437 ]--- CC: stable@kernel.org # 2.6.37+ Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'drivers/oprofile')
-rw-r--r--drivers/oprofile/oprof.c29
-rw-r--r--drivers/oprofile/timer_int.c1
2 files changed, 25 insertions, 5 deletions
diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index dccd8636095c..f8c752e408a6 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -239,26 +239,45 @@ int oprofile_set_ulong(unsigned long *addr, unsigned long val)
return err;
}
+static int timer_mode;
+
static int __init oprofile_init(void)
{
int err;
+ /* always init architecture to setup backtrace support */
err = oprofile_arch_init(&oprofile_ops);
- if (err < 0 || timer) {
- printk(KERN_INFO "oprofile: using timer interrupt.\n");
+
+ timer_mode = err || timer; /* fall back to timer mode on errors */
+ if (timer_mode) {
+ if (!err)
+ oprofile_arch_exit();
err = oprofile_timer_init(&oprofile_ops);
if (err)
return err;
}
- return oprofilefs_register();
+
+ err = oprofilefs_register();
+ if (!err)
+ return 0;
+
+ /* failed */
+ if (timer_mode)
+ oprofile_timer_exit();
+ else
+ oprofile_arch_exit();
+
+ return err;
}
static void __exit oprofile_exit(void)
{
- oprofile_timer_exit();
oprofilefs_unregister();
- oprofile_arch_exit();
+ if (timer_mode)
+ oprofile_timer_exit();
+ else
+ oprofile_arch_exit();
}
diff --git a/drivers/oprofile/timer_int.c b/drivers/oprofile/timer_int.c
index 3ef44624f510..878fba126582 100644
--- a/drivers/oprofile/timer_int.c
+++ b/drivers/oprofile/timer_int.c
@@ -110,6 +110,7 @@ int oprofile_timer_init(struct oprofile_operations *ops)
ops->start = oprofile_hrtimer_start;
ops->stop = oprofile_hrtimer_stop;
ops->cpu_type = "timer";
+ printk(KERN_INFO "oprofile: using timer interrupt.\n");
return 0;
}