From 87121ca504fd1d963a66b3fb0c72054b0fd9a177 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Fri, 7 Oct 2011 16:31:46 +0200 Subject: 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: [] 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:[] [] 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: [] op_nmi_exit+0x15/0x17 [oprofile] [] oprofile_arch_exit+0xe/0x10 [oprofile] [] oprofile_exit+0x13/0x15 [oprofile] [] sys_delete_module+0x1c3/0x22f [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] 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 [] unregister_syscore_ops+0x41/0x58 RSP CR2: 0000000000000008 ---[ end trace 06d4e95b6aa3b437 ]--- CC: stable@kernel.org # 2.6.37+ Signed-off-by: Robert Richter --- drivers/oprofile/oprof.c | 29 ++++++++++++++++++++++++----- drivers/oprofile/timer_int.c | 1 + 2 files changed, 25 insertions(+), 5 deletions(-) (limited to 'drivers/oprofile') diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c index dccd8636095..f8c752e408a 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 3ef44624f51..878fba12658 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; } -- cgit v1.2.3 From 75c43a20b220f885c39ffa7cdbbb1191e257a9a9 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Fri, 14 Oct 2011 15:46:10 +0200 Subject: oprofile: Remove exit function for timer mode Remove exit functions by moving init/exit code to oprofile's setup/ shutdown functions. Doing so the oprofile module exit code will be easier and less error-prone. Signed-off-by: Robert Richter --- drivers/oprofile/oprof.c | 8 ++------ drivers/oprofile/timer_int.c | 30 +++++++++++++++--------------- 2 files changed, 17 insertions(+), 21 deletions(-) (limited to 'drivers/oprofile') diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c index f8c752e408a..f7cd06967ae 100644 --- a/drivers/oprofile/oprof.c +++ b/drivers/oprofile/oprof.c @@ -262,9 +262,7 @@ static int __init oprofile_init(void) return 0; /* failed */ - if (timer_mode) - oprofile_timer_exit(); - else + if (!timer_mode) oprofile_arch_exit(); return err; @@ -274,9 +272,7 @@ static int __init oprofile_init(void) static void __exit oprofile_exit(void) { oprofilefs_unregister(); - if (timer_mode) - oprofile_timer_exit(); - else + if (!timer_mode) oprofile_arch_exit(); } diff --git a/drivers/oprofile/timer_int.c b/drivers/oprofile/timer_int.c index 878fba12658..93404f72dfa 100644 --- a/drivers/oprofile/timer_int.c +++ b/drivers/oprofile/timer_int.c @@ -97,24 +97,24 @@ static struct notifier_block __refdata oprofile_cpu_notifier = { .notifier_call = oprofile_cpu_notify, }; -int oprofile_timer_init(struct oprofile_operations *ops) +static int oprofile_hrtimer_setup(void) { - int rc; - - rc = register_hotcpu_notifier(&oprofile_cpu_notifier); - if (rc) - return rc; - ops->create_files = NULL; - ops->setup = NULL; - ops->shutdown = NULL; - ops->start = oprofile_hrtimer_start; - ops->stop = oprofile_hrtimer_stop; - ops->cpu_type = "timer"; - printk(KERN_INFO "oprofile: using timer interrupt.\n"); - return 0; + return register_hotcpu_notifier(&oprofile_cpu_notifier); } -void oprofile_timer_exit(void) +static void oprofile_hrtimer_shutdown(void) { unregister_hotcpu_notifier(&oprofile_cpu_notifier); } + +int oprofile_timer_init(struct oprofile_operations *ops) +{ + ops->create_files = NULL; + ops->setup = oprofile_hrtimer_setup; + ops->shutdown = oprofile_hrtimer_shutdown; + ops->start = oprofile_hrtimer_start; + ops->stop = oprofile_hrtimer_stop; + ops->cpu_type = "timer"; + printk(KERN_INFO "oprofile: using timer interrupt.\n"); + return 0; +} -- cgit v1.2.3 From dcfce4a095932e6e95d83ad982be3609947963bc Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Tue, 11 Oct 2011 17:11:08 +0200 Subject: oprofile, x86: Reimplement nmi timer mode using perf event The legacy x86 nmi watchdog code was removed with the implementation of the perf based nmi watchdog. This broke Oprofile's nmi timer mode. To run nmi timer mode we relied on a continuous ticking nmi source which the nmi watchdog provided. The nmi tick was no longer available and current watchdog can not be used anymore since it runs with very long periods in the range of seconds. This patch reimplements the nmi timer mode using a perf counter nmi source. V2: * removing pr_info() * fix undefined reference to `__udivdi3' for 32 bit build * fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb * removed nmi timer setup in arch/x86 * implemented function stubs for op_nmi_init/exit() * made code more readable in oprofile_init() V3: * fix architectural initialization in oprofile_init() * fix CONFIG_OPROFILE_NMI_TIMER dependencies Acked-by: Peter Zijlstra Signed-off-by: Robert Richter --- drivers/oprofile/nmi_timer_int.c | 173 +++++++++++++++++++++++++++++++++++++++ drivers/oprofile/oprof.c | 24 +++--- drivers/oprofile/oprof.h | 9 ++ 3 files changed, 193 insertions(+), 13 deletions(-) create mode 100644 drivers/oprofile/nmi_timer_int.c (limited to 'drivers/oprofile') diff --git a/drivers/oprofile/nmi_timer_int.c b/drivers/oprofile/nmi_timer_int.c new file mode 100644 index 00000000000..76f1c9357f3 --- /dev/null +++ b/drivers/oprofile/nmi_timer_int.c @@ -0,0 +1,173 @@ +/** + * @file nmi_timer_int.c + * + * @remark Copyright 2011 Advanced Micro Devices, Inc. + * + * @author Robert Richter + */ + +#include +#include +#include +#include +#include + +#ifdef CONFIG_OPROFILE_NMI_TIMER + +static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events); +static int ctr_running; + +static struct perf_event_attr nmi_timer_attr = { + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_CPU_CYCLES, + .size = sizeof(struct perf_event_attr), + .pinned = 1, + .disabled = 1, +}; + +static void nmi_timer_callback(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + event->hw.interrupts = 0; /* don't throttle interrupts */ + oprofile_add_sample(regs, 0); +} + +static int nmi_timer_start_cpu(int cpu) +{ + struct perf_event *event = per_cpu(nmi_timer_events, cpu); + + if (!event) { + event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL, + nmi_timer_callback, NULL); + if (IS_ERR(event)) + return PTR_ERR(event); + per_cpu(nmi_timer_events, cpu) = event; + } + + if (event && ctr_running) + perf_event_enable(event); + + return 0; +} + +static void nmi_timer_stop_cpu(int cpu) +{ + struct perf_event *event = per_cpu(nmi_timer_events, cpu); + + if (event && ctr_running) + perf_event_disable(event); +} + +static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action, + void *data) +{ + int cpu = (unsigned long)data; + switch (action) { + case CPU_DOWN_FAILED: + case CPU_ONLINE: + nmi_timer_start_cpu(cpu); + break; + case CPU_DOWN_PREPARE: + nmi_timer_stop_cpu(cpu); + break; + } + return NOTIFY_DONE; +} + +static struct notifier_block nmi_timer_cpu_nb = { + .notifier_call = nmi_timer_cpu_notifier +}; + +static int nmi_timer_start(void) +{ + int cpu; + + get_online_cpus(); + ctr_running = 1; + for_each_online_cpu(cpu) + nmi_timer_start_cpu(cpu); + put_online_cpus(); + + return 0; +} + +static void nmi_timer_stop(void) +{ + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) + nmi_timer_stop_cpu(cpu); + ctr_running = 0; + put_online_cpus(); +} + +static void nmi_timer_shutdown(void) +{ + struct perf_event *event; + int cpu; + + get_online_cpus(); + unregister_cpu_notifier(&nmi_timer_cpu_nb); + for_each_possible_cpu(cpu) { + event = per_cpu(nmi_timer_events, cpu); + if (!event) + continue; + perf_event_disable(event); + per_cpu(nmi_timer_events, cpu) = NULL; + perf_event_release_kernel(event); + } + + put_online_cpus(); +} + +static int nmi_timer_setup(void) +{ + int cpu, err; + u64 period; + + /* clock cycles per tick: */ + period = (u64)cpu_khz * 1000; + do_div(period, HZ); + nmi_timer_attr.sample_period = period; + + get_online_cpus(); + err = register_cpu_notifier(&nmi_timer_cpu_nb); + if (err) + goto out; + /* can't attach events to offline cpus: */ + for_each_online_cpu(cpu) { + err = nmi_timer_start_cpu(cpu); + if (err) + break; + } + if (err) + nmi_timer_shutdown(); +out: + put_online_cpus(); + return err; +} + +int __init op_nmi_timer_init(struct oprofile_operations *ops) +{ + int err = 0; + + err = nmi_timer_setup(); + if (err) + return err; + nmi_timer_shutdown(); /* only check, don't alloc */ + + ops->create_files = NULL; + ops->setup = nmi_timer_setup; + ops->shutdown = nmi_timer_shutdown; + ops->start = nmi_timer_start; + ops->stop = nmi_timer_stop; + ops->cpu_type = "timer"; + + printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); + + return 0; +} + +#endif diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c index f7cd06967ae..ed2c3ec0702 100644 --- a/drivers/oprofile/oprof.c +++ b/drivers/oprofile/oprof.c @@ -246,26 +246,24 @@ static int __init oprofile_init(void) int err; /* always init architecture to setup backtrace support */ + timer_mode = 0; err = oprofile_arch_init(&oprofile_ops); + if (!err) { + if (!timer && !oprofilefs_register()) + return 0; + oprofile_arch_exit(); + } - timer_mode = err || timer; /* fall back to timer mode on errors */ - if (timer_mode) { - if (!err) - oprofile_arch_exit(); + /* setup timer mode: */ + timer_mode = 1; + /* no nmi timer mode if oprofile.timer is set */ + if (timer || op_nmi_timer_init(&oprofile_ops)) { err = oprofile_timer_init(&oprofile_ops); if (err) return err; } - err = oprofilefs_register(); - if (!err) - return 0; - - /* failed */ - if (!timer_mode) - oprofile_arch_exit(); - - return err; + return oprofilefs_register(); } diff --git a/drivers/oprofile/oprof.h b/drivers/oprofile/oprof.h index 177b73de5e5..769fb0fcac4 100644 --- a/drivers/oprofile/oprof.h +++ b/drivers/oprofile/oprof.h @@ -36,6 +36,15 @@ struct dentry; void oprofile_create_files(struct super_block *sb, struct dentry *root); int oprofile_timer_init(struct oprofile_operations *ops); void oprofile_timer_exit(void); +#ifdef CONFIG_OPROFILE_NMI_TIMER +int op_nmi_timer_init(struct oprofile_operations *ops); +#else +static inline int op_nmi_timer_init(struct oprofile_operations *ops) +{ + return -ENODEV; +} +#endif + int oprofile_set_ulong(unsigned long *addr, unsigned long val); int oprofile_set_timeout(unsigned long time); -- cgit v1.2.3