From 944ac4259e39801c843a915c3da8194ac9af0440 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 23 Oct 2008 19:26:08 -0400 Subject: ftrace: ftrace dump on oops control Impact: add (default-off) dump-trace-on-oops flag Currently, ftrace is set up to dump its contents to the console if the kernel panics or oops. This can be annoying if you have trace data in the buffers and you experience an oops, but the trace data is old or static. Usually when you want ftrace to dump its contents is when you are debugging your system and you have set up ftrace to trace the events leading to an oops. This patch adds a control variable called "ftrace_dump_on_oops" that will enable the ftrace dump to console on oops. This variable is default off but a developer can enable it either through the kernel command line by adding "ftrace_dump_on_oops" or at run time by setting (or disabling) /proc/sys/kernel/ftrace_dump_on_oops. v2: Replaced /** with /* as Randy explained that kernel-doc does not yet handle variables. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/sysctl.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a13bd4dfaeb..84754f5801e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -484,6 +484,16 @@ static struct ctl_table kern_table[] = { .proc_handler = &ftrace_enable_sysctl, }, #endif +#ifdef CONFIG_TRACING + { + .ctl_name = CTL_UNNUMBERED, + .procname = "ftrace_dump_on_opps", + .data = &ftrace_dump_on_oops, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, +#endif #ifdef CONFIG_MODULES { .ctl_name = KERN_MODPROBE, -- cgit v1.2.3-70-g09d2 From 3299b4dd1180762da831be5eb6adc44553eaec26 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Nov 2008 11:58:21 +0100 Subject: ftrace: sysctl typo Impact: fix sysctl name typo Steve must have needed more coffee ;-) Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 6b6b727258b..65d4a9ba79e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -487,7 +487,7 @@ static struct ctl_table kern_table[] = { #ifdef CONFIG_TRACING { .ctl_name = CTL_UNNUMBERED, - .procname = "ftrace_dump_on_opps", + .procname = "ftrace_dump_on_oops", .data = &ftrace_dump_on_oops, .maxlen = sizeof(int), .mode = 0644, -- cgit v1.2.3-70-g09d2 From 76aac0e9a17742e60d408be1a706e9aaad370891 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 14 Nov 2008 10:39:12 +1100 Subject: CRED: Wrap task credential accesses in the core kernel Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells Reviewed-by: James Morris Acked-by: Serge Hallyn Cc: Al Viro Cc: linux-audit@redhat.com Cc: containers@lists.linux-foundation.org Cc: linux-mm@kvack.org Signed-off-by: James Morris --- kernel/acct.c | 7 +++---- kernel/auditsc.c | 6 ++++-- kernel/cgroup.c | 9 +++++---- kernel/futex.c | 8 +++++--- kernel/futex_compat.c | 3 ++- kernel/ptrace.c | 15 +++++++++------ kernel/sched.c | 11 +++++++---- kernel/signal.c | 15 +++++++++------ kernel/sys.c | 16 ++++++++-------- kernel/sysctl.c | 2 +- kernel/timer.c | 8 ++++---- kernel/user_namespace.c | 2 +- mm/mempolicy.c | 7 +++++-- mm/migrate.c | 7 +++++-- mm/shmem.c | 8 ++++---- 15 files changed, 72 insertions(+), 52 deletions(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/acct.c b/kernel/acct.c index f6006a60df5..d57b7cbb98b 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -530,15 +530,14 @@ static void do_acct_process(struct bsd_acct_struct *acct, do_div(elapsed, AHZ); ac.ac_btime = get_seconds() - elapsed; /* we really need to bite the bullet and change layout */ - ac.ac_uid = current->uid; - ac.ac_gid = current->gid; + current_uid_gid(&ac.ac_uid, &ac.ac_gid); #if ACCT_VERSION==2 ac.ac_ahz = AHZ; #endif #if ACCT_VERSION==1 || ACCT_VERSION==2 /* backward-compatible 16 bit fields */ - ac.ac_uid16 = current->uid; - ac.ac_gid16 = current->gid; + ac.ac_uid16 = ac.ac_uid; + ac.ac_gid16 = ac.ac_gid; #endif #if ACCT_VERSION==3 ac.ac_pid = task_tgid_nr_ns(current, ns); diff --git a/kernel/auditsc.c b/kernel/auditsc.c index cef34235b36..9c7e47ae457 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2628,7 +2628,8 @@ void audit_core_dumps(long signr) { struct audit_buffer *ab; u32 sid; - uid_t auid = audit_get_loginuid(current); + uid_t auid = audit_get_loginuid(current), uid; + gid_t gid; unsigned int sessionid = audit_get_sessionid(current); if (!audit_enabled) @@ -2638,8 +2639,9 @@ void audit_core_dumps(long signr) return; ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND); + current_uid_gid(&uid, &gid); audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u", - auid, current->uid, current->gid, sessionid); + auid, uid, gid, sessionid); security_task_getsecid(current, &sid); if (sid) { char *ctx = NULL; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 35eebd5510c..78f9b310c4f 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -571,8 +571,8 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) if (inode) { inode->i_mode = mode; - inode->i_uid = current->fsuid; - inode->i_gid = current->fsgid; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info; @@ -1279,6 +1279,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) { struct task_struct *tsk; + uid_t euid; int ret; if (pid) { @@ -1291,8 +1292,8 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) get_task_struct(tsk); rcu_read_unlock(); - if ((current->euid) && (current->euid != tsk->uid) - && (current->euid != tsk->suid)) { + euid = current_euid(); + if (euid && euid != tsk->uid && euid != tsk->suid) { put_task_struct(tsk); return -EACCES; } diff --git a/kernel/futex.c b/kernel/futex.c index 8af10027514..e06962132aa 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -439,10 +439,11 @@ static void free_pi_state(struct futex_pi_state *pi_state) static struct task_struct * futex_find_get_task(pid_t pid) { struct task_struct *p; + uid_t euid = current_euid(); rcu_read_lock(); p = find_task_by_vpid(pid); - if (!p || ((current->euid != p->euid) && (current->euid != p->uid))) + if (!p || (euid != p->euid && euid != p->uid)) p = ERR_PTR(-ESRCH); else get_task_struct(p); @@ -1829,6 +1830,7 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr, { struct robust_list_head __user *head; unsigned long ret; + uid_t euid = current_euid(); if (!futex_cmpxchg_enabled) return -ENOSYS; @@ -1844,8 +1846,8 @@ sys_get_robust_list(int pid, struct robust_list_head __user * __user *head_ptr, if (!p) goto err_unlock; ret = -EPERM; - if ((current->euid != p->euid) && (current->euid != p->uid) && - !capable(CAP_SYS_PTRACE)) + if (euid != p->euid && euid != p->uid && + !capable(CAP_SYS_PTRACE)) goto err_unlock; head = p->robust_list; rcu_read_unlock(); diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c index 04ac3a9e42c..3254d4e41e8 100644 --- a/kernel/futex_compat.c +++ b/kernel/futex_compat.c @@ -135,6 +135,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, { struct compat_robust_list_head __user *head; unsigned long ret; + uid_t euid = current_euid(); if (!futex_cmpxchg_enabled) return -ENOSYS; @@ -150,7 +151,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, if (!p) goto err_unlock; ret = -EPERM; - if ((current->euid != p->euid) && (current->euid != p->uid) && + if (euid != p->euid && euid != p->uid && !capable(CAP_SYS_PTRACE)) goto err_unlock; head = p->compat_robust_list; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 1e68e4c39e2..937f6b5b200 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -123,16 +123,19 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode) * because setting up the necessary parent/child relationship * or halting the specified task is impossible. */ + uid_t uid; + gid_t gid; int dumpable = 0; /* Don't let security modules deny introspection */ if (task == current) return 0; - if (((current->uid != task->euid) || - (current->uid != task->suid) || - (current->uid != task->uid) || - (current->gid != task->egid) || - (current->gid != task->sgid) || - (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE)) + current_uid_gid(&uid, &gid); + if ((uid != task->euid || + uid != task->suid || + uid != task->uid || + gid != task->egid || + gid != task->sgid || + gid != task->gid) && !capable(CAP_SYS_PTRACE)) return -EPERM; smp_rmb(); if (task->mm) diff --git a/kernel/sched.c b/kernel/sched.c index e8819bc6f46..c3b8b1fcde0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5128,6 +5128,7 @@ static int __sched_setscheduler(struct task_struct *p, int policy, unsigned long flags; const struct sched_class *prev_class = p->sched_class; struct rq *rq; + uid_t euid; /* may grab non-irq protected spin_locks */ BUG_ON(in_interrupt()); @@ -5180,8 +5181,9 @@ recheck: return -EPERM; /* can't change other user's priorities */ - if ((current->euid != p->euid) && - (current->euid != p->uid)) + euid = current_euid(); + if (euid != p->euid && + euid != p->uid) return -EPERM; } @@ -5392,6 +5394,7 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask) cpumask_t cpus_allowed; cpumask_t new_mask = *in_mask; struct task_struct *p; + uid_t euid; int retval; get_online_cpus(); @@ -5412,9 +5415,9 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask) get_task_struct(p); read_unlock(&tasklist_lock); + euid = current_euid(); retval = -EPERM; - if ((current->euid != p->euid) && (current->euid != p->uid) && - !capable(CAP_SYS_NICE)) + if (euid != p->euid && euid != p->uid && !capable(CAP_SYS_NICE)) goto out_unlock; retval = security_task_setscheduler(p, 0, NULL); diff --git a/kernel/signal.c b/kernel/signal.c index 4530fc65445..167b535fe1a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -567,6 +567,7 @@ static int check_kill_permission(int sig, struct siginfo *info, struct task_struct *t) { struct pid *sid; + uid_t uid, euid; int error; if (!valid_signal(sig)) @@ -579,8 +580,10 @@ static int check_kill_permission(int sig, struct siginfo *info, if (error) return error; - if ((current->euid ^ t->suid) && (current->euid ^ t->uid) && - (current->uid ^ t->suid) && (current->uid ^ t->uid) && + uid = current_uid(); + euid = current_euid(); + if ((euid ^ t->suid) && (euid ^ t->uid) && + (uid ^ t->suid) && (uid ^ t->uid) && !capable(CAP_KILL)) { switch (sig) { case SIGCONT: @@ -844,7 +847,7 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, q->info.si_errno = 0; q->info.si_code = SI_USER; q->info.si_pid = task_pid_vnr(current); - q->info.si_uid = current->uid; + q->info.si_uid = current_uid(); break; case (unsigned long) SEND_SIG_PRIV: q->info.si_signo = sig; @@ -1598,7 +1601,7 @@ void ptrace_notify(int exit_code) info.si_signo = SIGTRAP; info.si_code = exit_code; info.si_pid = task_pid_vnr(current); - info.si_uid = current->uid; + info.si_uid = current_uid(); /* Let the debugger run. */ spin_lock_irq(¤t->sighand->siglock); @@ -2211,7 +2214,7 @@ sys_kill(pid_t pid, int sig) info.si_errno = 0; info.si_code = SI_USER; info.si_pid = task_tgid_vnr(current); - info.si_uid = current->uid; + info.si_uid = current_uid(); return kill_something_info(sig, &info, pid); } @@ -2228,7 +2231,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig) info.si_errno = 0; info.si_code = SI_TKILL; info.si_pid = task_tgid_vnr(current); - info.si_uid = current->uid; + info.si_uid = current_uid(); rcu_read_lock(); p = find_task_by_vpid(pid); diff --git a/kernel/sys.c b/kernel/sys.c index 31deba8f7d1..ed5c29c748a 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -114,10 +114,10 @@ void (*pm_power_off_prepare)(void); static int set_one_prio(struct task_struct *p, int niceval, int error) { + uid_t euid = current_euid(); int no_nice; - if (p->uid != current->euid && - p->euid != current->euid && !capable(CAP_SYS_NICE)) { + if (p->uid != euid && p->euid != euid && !capable(CAP_SYS_NICE)) { error = -EPERM; goto out; } @@ -176,16 +176,16 @@ asmlinkage long sys_setpriority(int which, int who, int niceval) case PRIO_USER: user = current->user; if (!who) - who = current->uid; + who = current_uid(); else - if ((who != current->uid) && !(user = find_user(who))) + if (who != current_uid() && !(user = find_user(who))) goto out_unlock; /* No processes for this user */ do_each_thread(g, p) if (p->uid == who) error = set_one_prio(p, niceval, error); while_each_thread(g, p); - if (who != current->uid) + if (who != current_uid()) free_uid(user); /* For find_user() */ break; } @@ -238,9 +238,9 @@ asmlinkage long sys_getpriority(int which, int who) case PRIO_USER: user = current->user; if (!who) - who = current->uid; + who = current_uid(); else - if ((who != current->uid) && !(user = find_user(who))) + if (who != current_uid() && !(user = find_user(who))) goto out_unlock; /* No processes for this user */ do_each_thread(g, p) @@ -250,7 +250,7 @@ asmlinkage long sys_getpriority(int which, int who) retval = niceval; } while_each_thread(g, p); - if (who != current->uid) + if (who != current_uid()) free_uid(user); /* for find_user() */ break; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 9d048fa2d90..511031381c3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1641,7 +1641,7 @@ out: static int test_perm(int mode, int op) { - if (!current->euid) + if (!current_euid()) mode >>= 6; else if (in_egroup_p(0)) mode >>= 3; diff --git a/kernel/timer.c b/kernel/timer.c index 56becf373c5..b54e4646cee 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1123,25 +1123,25 @@ asmlinkage long sys_getppid(void) asmlinkage long sys_getuid(void) { /* Only we change this so SMP safe */ - return current->uid; + return current_uid(); } asmlinkage long sys_geteuid(void) { /* Only we change this so SMP safe */ - return current->euid; + return current_euid(); } asmlinkage long sys_getgid(void) { /* Only we change this so SMP safe */ - return current->gid; + return current_gid(); } asmlinkage long sys_getegid(void) { /* Only we change this so SMP safe */ - return current->egid; + return current_egid(); } #endif diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 532858fa5b8..f82730adea0 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -38,7 +38,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns) } /* Reset current->user with a new one */ - new_user = alloc_uid(ns, current->uid); + new_user = alloc_uid(ns, current_uid()); if (!new_user) { free_uid(ns->root_user); kfree(ns); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 36f42573a33..07a96474077 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1115,6 +1115,7 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode, nodemask_t old; nodemask_t new; nodemask_t task_nodes; + uid_t uid, euid; int err; err = get_nodes(&old, old_nodes, maxnode); @@ -1144,8 +1145,10 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode, * capabilities, superuser privileges or the same * userid as the target process. */ - if ((current->euid != task->suid) && (current->euid != task->uid) && - (current->uid != task->suid) && (current->uid != task->uid) && + uid = current_uid(); + euid = current_euid(); + if (euid != task->suid && euid != task->uid && + uid != task->suid && uid != task->uid && !capable(CAP_SYS_NICE)) { err = -EPERM; goto out; diff --git a/mm/migrate.c b/mm/migrate.c index 6602941bfab..6263c24c4af 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1048,6 +1048,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, struct task_struct *task; struct mm_struct *mm; int err; + uid_t uid, euid; /* Check flags */ if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) @@ -1075,8 +1076,10 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, * capabilities, superuser privileges or the same * userid as the target process. */ - if ((current->euid != task->suid) && (current->euid != task->uid) && - (current->uid != task->suid) && (current->uid != task->uid) && + uid = current_uid(); + euid = current_euid(); + if (euid != task->suid && euid != task->uid && + uid != task->suid && uid != task->uid && !capable(CAP_SYS_NICE)) { err = -EPERM; goto out; diff --git a/mm/shmem.c b/mm/shmem.c index 0ed075215e5..f1b0d4871f3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1513,8 +1513,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) inode = new_inode(sb); if (inode) { inode->i_mode = mode; - inode->i_uid = current->fsuid; - inode->i_gid = current->fsgid; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); inode->i_blocks = 0; inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; @@ -2278,8 +2278,8 @@ static int shmem_fill_super(struct super_block *sb, sbinfo->max_blocks = 0; sbinfo->max_inodes = 0; sbinfo->mode = S_IRWXUGO | S_ISVTX; - sbinfo->uid = current->fsuid; - sbinfo->gid = current->fsgid; + sbinfo->uid = current_fsuid(); + sbinfo->gid = current_fsgid(); sbinfo->mpol = NULL; sb->s_fs_info = sbinfo; -- cgit v1.2.3-70-g09d2 From f38f1d2aa5a3520cf05da7cd6bd12fe2b0c509b7 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 16 Dec 2008 23:06:40 -0500 Subject: trace: add a way to enable or disable the stack tracer Impact: enhancement to stack tracer The stack tracer currently is either on when configured in or off when it is not. It can not be disabled when it is configured on. (besides disabling the function tracer that it uses) This patch adds a way to enable or disable the stack tracer at run time. It defaults off on bootup, but a kernel parameter 'stacktrace' has been added to enable it on bootup. A new sysctl has been added "kernel.stack_tracer_enabled" to let the user enable or disable the stack tracer at run time. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 4 +++ include/linux/ftrace.h | 8 ++++++ kernel/sysctl.c | 10 +++++++ kernel/trace/Kconfig | 13 +++++++--- kernel/trace/trace_stack.c | 52 ++++++++++++++++++++++++++++++++++--- 5 files changed, 79 insertions(+), 8 deletions(-) (limited to 'kernel/sysctl.c') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2919a2e9193..edab81c1318 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -89,6 +89,7 @@ parameter is applicable: SPARC Sparc architecture is enabled. SWSUSP Software suspend (hibernation) is enabled. SUSPEND System suspend states are enabled. + FTRACE Function tracing enabled. TS Appropriate touchscreen support is enabled. USB USB support is enabled. USBHID USB Human Interface Device support is enabled. @@ -2173,6 +2174,9 @@ and is between 256 and 4096 characters. It is defined in the file st= [HW,SCSI] SCSI tape parameters (buffers, etc.) See Documentation/scsi/st.txt. + stacktrace [FTRACE] + Enabled the stack tracer on boot up. + sti= [PARISC,HW] Format: Set the STI (builtin display/keyboard on the HP-PARISC diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 44020f31bd8..6b0db53caa7 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -86,6 +86,14 @@ static inline void ftrace_stop(void) { } static inline void ftrace_start(void) { } #endif /* CONFIG_FUNCTION_TRACER */ +#ifdef CONFIG_STACK_TRACER +extern int stack_tracer_enabled; +int +stack_trace_sysctl(struct ctl_table *table, int write, + struct file *file, void __user *buffer, size_t *lenp, + loff_t *ppos); +#endif + #ifdef CONFIG_DYNAMIC_FTRACE /* asm/ftrace.h must be defined for archs supporting dynamic ftrace */ #include diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c83f566e940..6ac501a2dcc 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -487,6 +487,16 @@ static struct ctl_table kern_table[] = { .proc_handler = &ftrace_enable_sysctl, }, #endif +#ifdef CONFIG_STACK_TRACER + { + .ctl_name = CTL_UNNUMBERED, + .procname = "stack_tracer_enabled", + .data = &stack_tracer_enabled, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &stack_trace_sysctl, + }, +#endif #ifdef CONFIG_TRACING { .ctl_name = CTL_UNNUMBERED, diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d8bae6f4219..e2a4ff6fc3a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -244,10 +244,15 @@ config STACK_TRACER This tracer works by hooking into every function call that the kernel executes, and keeping a maximum stack depth value and - stack-trace saved. Because this logic has to execute in every - kernel function, all the time, this option can slow down the - kernel measurably and is generally intended for kernel - developers only. + stack-trace saved. If this is configured with DYNAMIC_FTRACE + then it will not have any overhead while the stack tracer + is disabled. + + To enable the stack tracer on bootup, pass in 'stacktrace' + on the kernel command line. + + The stack tracer can also be enabled or disabled via the + sysctl kernel.stack_tracer_enabled Say N if unsure. diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 0b863f2cbc8..4842c969c78 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include "trace.h" @@ -31,6 +32,10 @@ static raw_spinlock_t max_stack_lock = static int stack_trace_disabled __read_mostly; static DEFINE_PER_CPU(int, trace_active); +static DEFINE_MUTEX(stack_sysctl_mutex); + +int stack_tracer_enabled; +static int last_stack_tracer_enabled; static inline void check_stack(void) { @@ -174,7 +179,7 @@ stack_max_size_write(struct file *filp, const char __user *ubuf, return count; } -static struct file_operations stack_max_size_fops = { +static const struct file_operations stack_max_size_fops = { .open = tracing_open_generic, .read = stack_max_size_read, .write = stack_max_size_write, @@ -272,7 +277,7 @@ static int t_show(struct seq_file *m, void *v) return 0; } -static struct seq_operations stack_trace_seq_ops = { +static const struct seq_operations stack_trace_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, @@ -288,12 +293,48 @@ static int stack_trace_open(struct inode *inode, struct file *file) return ret; } -static struct file_operations stack_trace_fops = { +static const struct file_operations stack_trace_fops = { .open = stack_trace_open, .read = seq_read, .llseek = seq_lseek, }; +int +stack_trace_sysctl(struct ctl_table *table, int write, + struct file *file, void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + + mutex_lock(&stack_sysctl_mutex); + + ret = proc_dointvec(table, write, file, buffer, lenp, ppos); + + if (ret || !write || + (last_stack_tracer_enabled == stack_tracer_enabled)) + goto out; + + last_stack_tracer_enabled = stack_tracer_enabled; + + if (stack_tracer_enabled) + register_ftrace_function(&trace_ops); + else + unregister_ftrace_function(&trace_ops); + + out: + mutex_unlock(&stack_sysctl_mutex); + return ret; +} + +static int start_stack_trace __initdata; + +static __init int enable_stacktrace(char *str) +{ + start_stack_trace = 1; + return 1; +} +__setup("stacktrace", enable_stacktrace); + static __init int stack_trace_init(void) { struct dentry *d_tracer; @@ -311,7 +352,10 @@ static __init int stack_trace_init(void) if (!entry) pr_warning("Could not create debugfs 'stack_trace' entry\n"); - register_ftrace_function(&trace_ops); + if (start_stack_trace) { + register_ftrace_function(&trace_ops); + stack_tracer_enabled = 1; + } return 0; } -- cgit v1.2.3-70-g09d2