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oprofile, x86: Fix crash when unloading module (nmi timer mode)
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commit 97f7f81 upstream.

If oprofile uses the nmi timer interrupt there is a crash while
unloading the module. The bug can be triggered with oprofile build as
module and kernel parameter nolapic set. This patch fixes this.

oprofile: using NMI timer interrupt.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58
PGD 42dbca067 PUD 41da6a067 PMD 0
Oops: 0002 [#1] PREEMPT SMP
CPU 5
Modules linked in: oprofile(-) [last unloaded: oprofile]

Pid: 2518, comm: modprobe Not tainted 3.1.0-rc7-00019-gb2fb49d torvalds#19 Advanced Micro Device Anaheim/Anaheim
RIP: 0010:[<ffffffff8123c226>]  [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58
RSP: 0018:ffff88041ef71e98  EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffffffffa0017100 RCX: dead000000200200
RDX: 0000000000000000 RSI: dead000000100100 RDI: ffffffff8178c620
RBP: ffff88041ef71ea8 R08: 0000000000000001 R09: 0000000000000082
R10: 0000000000000000 R11: ffff88041ef71de8 R12: 0000000000000080
R13: fffffffffffffff5 R14: 0000000000000001 R15: 0000000000610210
FS:  00007fc902f20700(0000) GS:ffff88042fd40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000008 CR3: 000000041cdb6000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 2518, threadinfo ffff88041ef70000, task ffff88041d348040)
Stack:
 ffff88041ef71eb8 ffffffffa0017790 ffff88041ef71eb8 ffffffffa0013532
 ffff88041ef71ec8 ffffffffa00132d6 ffff88041ef71ed8 ffffffffa00159b2
 ffff88041ef71f78 ffffffff81073115 656c69666f72706f 0000000000610200
Call Trace:
 [<ffffffffa0013532>] op_nmi_exit+0x15/0x17 [oprofile]
 [<ffffffffa00132d6>] oprofile_arch_exit+0xe/0x10 [oprofile]
 [<ffffffffa00159b2>] oprofile_exit+0x1e/0x20 [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 <ffff88041ef71e98>
CR2: 0000000000000008
---[ end trace 43a541a52956b7b0 ]---

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@gregkh
Robert Richter authored and gregkh committed Dec 9, 2011
1 parent b11ee9e commit a6ff8af
Showing 1 changed file with 5 additions and 2 deletions.
7 changes: 5 additions & 2 deletions arch/x86/oprofile/init.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ extern int op_nmi_timer_init(struct oprofile_operations *ops);
extern void op_nmi_exit(void);
extern void x86_backtrace(struct pt_regs * const regs, unsigned int depth);

static int nmi_timer;

int __init oprofile_arch_init(struct oprofile_operations *ops)
{
Expand All @@ -31,8 +32,9 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
#ifdef CONFIG_X86_LOCAL_APIC
ret = op_nmi_init(ops);
#endif
nmi_timer = (ret != 0);
#ifdef CONFIG_X86_IO_APIC
if (ret < 0)
if (nmi_timer)
ret = op_nmi_timer_init(ops);
#endif
ops->backtrace = x86_backtrace;
Expand All @@ -44,6 +46,7 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
void oprofile_arch_exit(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
op_nmi_exit();
if (!nmi_timer)
op_nmi_exit();
#endif
}

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