From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Dobriyan Subject: [PATCH v42] proc: add /proc/*/stack (was Re: linux-next: proc tree build failure) Date: Mon, 10 Nov 2008 11:42:29 +0300 Message-ID: <20081110084229.GA8690@x200.localdomain> References: <20081110162941.e9e9ef3a.sfr@canb.auug.org.au> <20081110055311.GA3138@x200.localdomain> <20081110073623.GA475@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20081110073623.GA475@elte.hu> Sender: linux-next-owner@vger.kernel.org To: Ingo Molnar Cc: Stephen Rothwell , linux-next@vger.kernel.org, Ken Chen , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On Mon, Nov 10, 2008 at 08:36:23AM +0100, Ingo Molnar wrote: > > * Alexey Dobriyan wrote: > > > On Mon, Nov 10, 2008 at 04:29:41PM +1100, Stephen Rothwell wrote: > > > Today's linux-next build (powerpc ppc64_defconfig) failed like this: > > > > > > fs/proc/base.c:2547: error: 'pid_stack' undeclared here (not in a function) > > > > > > Caused by an interaction of commits > > > 078e9901c02d4899db5b24f708b8dfbca8935891 ("stacktrace: > > > add /proc//stack to dump task's stack trace") and > > > 35f0b5fd7fab907a1119eaa614d9b24e5e225755 ("stacktrace: > > > convert /proc//stack to seqfiles") from the tip-core tree with commit > > > 5d8880e3e0fb96459c652ac5e1504b90c949b3b9 ("proc: remove '##' usage") from > > > the proc tree. > > > > > > The former added a new usage of INF (which the second converted to a > > > ONE). I added the following patch to the merge of the proc tree and can > > > carry it. > > > > Time to steal this /proc/*/stack from Ingo. :-) > > Alexey, would you like to carry them for v2.6.29? They are in a > separate tree here, the pull coordinates are below. > > Please preserve the sha1's (do not rebase/cherry-pick, etc.) so that i > can carry it too without causing confusion. Sorry, I can't. It's two commits, PROC_BLOCK_SIZE moving chunk is now unneeded, because seqfiles are in use, grabbing tasklist_lock for protection from task dissapearing is unneeded -- proc_single_show() pins task_struct, entry is added only to tgid table. So, here is final version: commit 12bf5a00732a5f9512081291097d0e4a3224e8a3 Author: Ken Chen Date: Mon Nov 10 11:26:08 2008 +0300 proc: add /proc/*/stack /proc/*/stack adds the ability to query a task's stack trace. It is more useful than /proc/*/wchan as it provides full stack trace instead of single depth. Example output: $ cat /proc/self/stack [] save_stack_trace_tsk+0x17/0x35 [] proc_pid_stack+0x4a/0x76 [] proc_single_show+0x4a/0x5e [] seq_read+0xf3/0x29f [] vfs_read+0x6d/0x91 [] sys_read+0x3b/0x60 [] syscall_call+0x7/0xb [] 0xffffffff Signed-off-by: Ken Chen Signed-off-by: Ingo Molnar Signed-off-by: Alexey Dobriyan diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index bcceb99..11f5b75 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -139,6 +139,7 @@ Table 1-1: Process specific entries in /proc statm Process memory status information status Process status in human readable form wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan + stack Report full stack trace, enable via CONFIG_STACKTRACE smaps Extension based on maps, the rss size for each mapped file .............................................................................. diff --git a/fs/proc/base.c b/fs/proc/base.c index 6e850e9..738ea78 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -65,6 +65,7 @@ #include #include #include +#include #include #include #include @@ -337,6 +338,37 @@ static int proc_pid_wchan(struct task_struct *task, char *buffer) } #endif /* CONFIG_KALLSYMS */ +#ifdef CONFIG_STACKTRACE + +#define MAX_STACK_TRACE_DEPTH 64 + +static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *task) +{ + struct stack_trace trace; + unsigned long *entries; + int i; + + entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL); + if (!entries) + return -ENOMEM; + + trace.nr_entries = 0; + trace.max_entries = MAX_STACK_TRACE_DEPTH; + trace.entries = entries; + trace.skip = 0; + save_stack_trace_tsk(task, &trace); + + for (i = 0; i < trace.nr_entries; i++) { + seq_printf(m, "[<%p>] %pS\n", + (void *)entries[i], (void *)entries[i]); + } + kfree(entries); + + return 0; +} +#endif + #ifdef CONFIG_SCHEDSTATS /* * Provides /proc/PID/schedstat @@ -2484,6 +2516,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_KALLSYMS INF("wchan", S_IRUGO, proc_pid_wchan), #endif +#ifdef CONFIG_STACKTRACE + ONE("stack", S_IRUSR, proc_pid_stack), +#endif #ifdef CONFIG_SCHEDSTATS INF("schedstat", S_IRUGO, proc_pid_schedstat), #endif @@ -2819,6 +2854,9 @@ static const struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_KALLSYMS INF("wchan", S_IRUGO, proc_pid_wchan), #endif +#ifdef CONFIG_STACKTRACE + ONE("stack", S_IRUSR, proc_pid_stack), +#endif #ifdef CONFIG_SCHEDSTATS INF("schedstat", S_IRUGO, proc_pid_schedstat), #endif