From 97f7f8189fe54e3cfe324ef9ad35064f3d2d3bff Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Mon, 10 Oct 2011 16:21:10 +0200 Subject: oprofile, x86: Fix crash when unloading module (nmi timer mode) 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: [] 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 #19 Advanced Micro Device Anaheim/Anaheim RIP: 0010:[] [] 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: [] op_nmi_exit+0x15/0x17 [oprofile] [] oprofile_arch_exit+0xe/0x10 [oprofile] [] oprofile_exit+0x1e/0x20 [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 43a541a52956b7b0 ]--- CC: stable@kernel.org # 2.6.37+ Signed-off-by: Robert Richter --- arch/x86/oprofile/init.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/x86/oprofile/init.c b/arch/x86/oprofile/init.c index cdfe4c54deca..f148cf652678 100644 --- a/arch/x86/oprofile/init.c +++ b/arch/x86/oprofile/init.c @@ -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) { @@ -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; @@ -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 } -- cgit v1.2.3 From 159a80b2142df709416ab369113de7d511c48331 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Tue, 11 Oct 2011 19:39:16 +0200 Subject: oprofile, x86: Add kernel parameter oprofile.cpu_type=timer We need this to better test x86 NMI timer mode. Otherwise it is very hard to setup systems with NMI timer enabled, but we have this e.g. in virtual machine environments. Signed-off-by: Robert Richter --- arch/x86/oprofile/nmi_int.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c index 68894fdc034b..7ca4d43e8988 100644 --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -613,24 +613,36 @@ static int __init p4_init(char **cpu_type) return 0; } -static int force_arch_perfmon; -static int force_cpu_type(const char *str, struct kernel_param *kp) +enum __force_cpu_type { + reserved = 0, /* do not force */ + timer, + arch_perfmon, +}; + +static int force_cpu_type; + +static int set_cpu_type(const char *str, struct kernel_param *kp) { - if (!strcmp(str, "arch_perfmon")) { - force_arch_perfmon = 1; + if (!strcmp(str, "timer")) { + force_cpu_type = timer; + printk(KERN_INFO "oprofile: forcing NMI timer mode\n"); + } else if (!strcmp(str, "arch_perfmon")) { + force_cpu_type = arch_perfmon; printk(KERN_INFO "oprofile: forcing architectural perfmon\n"); + } else { + force_cpu_type = 0; } return 0; } -module_param_call(cpu_type, force_cpu_type, NULL, NULL, 0); +module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0); static int __init ppro_init(char **cpu_type) { __u8 cpu_model = boot_cpu_data.x86_model; struct op_x86_model_spec *spec = &op_ppro_spec; /* default */ - if (force_arch_perfmon && cpu_has_arch_perfmon) + if (force_cpu_type == arch_perfmon && cpu_has_arch_perfmon) return 0; /* @@ -697,6 +709,9 @@ int __init op_nmi_init(struct oprofile_operations *ops) if (!cpu_has_apic) return -ENODEV; + if (force_cpu_type == timer) + return -ENODEV; + switch (vendor) { case X86_VENDOR_AMD: /* Needs to be at least an Athlon (or hammer in 32bit mode) */ -- 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 --- arch/Kconfig | 4 +++ arch/x86/oprofile/Makefile | 3 +- arch/x86/oprofile/init.c | 30 +++++------------- arch/x86/oprofile/nmi_timer_int.c | 66 --------------------------------------- 4 files changed, 13 insertions(+), 90 deletions(-) delete mode 100644 arch/x86/oprofile/nmi_timer_int.c (limited to 'arch') diff --git a/arch/Kconfig b/arch/Kconfig index 4b0669cbb3b0..2505740b81d2 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -30,6 +30,10 @@ config OPROFILE_EVENT_MULTIPLEX config HAVE_OPROFILE bool +config OPROFILE_NMI_TIMER + def_bool y + depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI + config KPROBES bool "Kprobes" depends on MODULES diff --git a/arch/x86/oprofile/Makefile b/arch/x86/oprofile/Makefile index 446902b2a6b6..1599f568f0e2 100644 --- a/arch/x86/oprofile/Makefile +++ b/arch/x86/oprofile/Makefile @@ -4,9 +4,8 @@ DRIVER_OBJS = $(addprefix ../../../drivers/oprofile/, \ oprof.o cpu_buffer.o buffer_sync.o \ event_buffer.o oprofile_files.o \ oprofilefs.o oprofile_stats.o \ - timer_int.o ) + timer_int.o nmi_timer_int.o ) oprofile-y := $(DRIVER_OBJS) init.o backtrace.o oprofile-$(CONFIG_X86_LOCAL_APIC) += nmi_int.o op_model_amd.o \ op_model_ppro.o op_model_p4.o -oprofile-$(CONFIG_X86_IO_APIC) += nmi_timer_int.o diff --git a/arch/x86/oprofile/init.c b/arch/x86/oprofile/init.c index f148cf652678..9e138d00ad36 100644 --- a/arch/x86/oprofile/init.c +++ b/arch/x86/oprofile/init.c @@ -16,37 +16,23 @@ * with the NMI mode driver. */ +#ifdef CONFIG_X86_LOCAL_APIC extern int op_nmi_init(struct oprofile_operations *ops); -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); +#else +static int op_nmi_init(struct oprofile_operations *ops) { return -ENODEV; } +static void op_nmi_exit(void) { } +#endif -static int nmi_timer; +extern void x86_backtrace(struct pt_regs * const regs, unsigned int depth); int __init oprofile_arch_init(struct oprofile_operations *ops) { - int ret; - - ret = -ENODEV; - -#ifdef CONFIG_X86_LOCAL_APIC - ret = op_nmi_init(ops); -#endif - nmi_timer = (ret != 0); -#ifdef CONFIG_X86_IO_APIC - if (nmi_timer) - ret = op_nmi_timer_init(ops); -#endif ops->backtrace = x86_backtrace; - - return ret; + return op_nmi_init(ops); } - void oprofile_arch_exit(void) { -#ifdef CONFIG_X86_LOCAL_APIC - if (!nmi_timer) - op_nmi_exit(); -#endif + op_nmi_exit(); } diff --git a/arch/x86/oprofile/nmi_timer_int.c b/arch/x86/oprofile/nmi_timer_int.c deleted file mode 100644 index 720bf5a53c51..000000000000 --- a/arch/x86/oprofile/nmi_timer_int.c +++ /dev/null @@ -1,66 +0,0 @@ -/** - * @file nmi_timer_int.c - * - * @remark Copyright 2003 OProfile authors - * @remark Read the file COPYING - * - * @author Zwane Mwaikambo - */ - -#include -#include -#include -#include -#include -#include - -#include -#include -#include - -static int profile_timer_exceptions_notify(struct notifier_block *self, - unsigned long val, void *data) -{ - struct die_args *args = (struct die_args *)data; - int ret = NOTIFY_DONE; - - switch (val) { - case DIE_NMI: - oprofile_add_sample(args->regs, 0); - ret = NOTIFY_STOP; - break; - default: - break; - } - return ret; -} - -static struct notifier_block profile_timer_exceptions_nb = { - .notifier_call = profile_timer_exceptions_notify, - .next = NULL, - .priority = NMI_LOW_PRIOR, -}; - -static int timer_start(void) -{ - if (register_die_notifier(&profile_timer_exceptions_nb)) - return 1; - return 0; -} - - -static void timer_stop(void) -{ - unregister_die_notifier(&profile_timer_exceptions_nb); - synchronize_sched(); /* Allow already-started NMIs to complete. */ -} - - -int __init op_nmi_timer_init(struct oprofile_operations *ops) -{ - ops->start = timer_start; - ops->stop = timer_stop; - ops->cpu_type = "timer"; - printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); - return 0; -} -- cgit v1.2.3