From: Namhyung Kim <namhyung.kim@lge.com> Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- include/linux/ftrace.h | 2 +- kernel/trace/ftrace.c | 10 +++++----- kernel/trace/trace_stack.c | 2 +- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 832422d706f4..c7687d8c0b30 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -396,7 +396,7 @@ ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos); ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos); -loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence); +loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence); int ftrace_regex_release(struct inode *inode, struct file *file); void __init diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 03953fbd1b2a..be2bcb7ab2f7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2688,7 +2688,7 @@ ftrace_notrace_open(struct inode *inode, struct file *file) } loff_t -ftrace_regex_lseek(struct file *file, loff_t offset, int whence) +ftrace_filter_lseek(struct file *file, loff_t offset, int whence) { loff_t ret; @@ -3613,7 +3613,7 @@ static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3621,7 +3621,7 @@ static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3826,8 +3826,8 @@ static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, + .llseek = ftrace_filter_lseek, .release = ftrace_graph_release, - .llseek = seq_lseek, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ @@ -4481,7 +4481,7 @@ static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, - .llseek = seq_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_pid_release, }; diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 8c3f37e2dc43..b20428c5efe2 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -382,7 +382,7 @@ static const struct file_operations stack_trace_filter_fops = { .open = stack_trace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; -- 1.7.11.7
From: Namhyung Kim <namhyung.kim@lge.com> The ftrace_graph_count can be decreased with a "!" pattern, so that the enabled flag should be updated too. Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- kernel/trace/ftrace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index be2bcb7ab2f7..3b5ef16692c5 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3779,7 +3779,11 @@ out: if (fail) return -EINVAL; - ftrace_graph_filter_enabled = 1; + if (*idx) + ftrace_graph_filter_enabled = 1; + else + ftrace_graph_filter_enabled = 0; + return 0; } -- 1.7.11.7
From: Namhyung Kim <namhyung.kim@lge.com> The ftrace_graph_count can be decreased with a "!" pattern, so that the enabled flag should be updated too. Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- kernel/trace/ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index be2bcb7ab2f7..daf8df20b764 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3779,7 +3779,8 @@ out: if (fail) return -EINVAL; - ftrace_graph_filter_enabled = 1; + ftrace_graph_filter_enabled = !!(*idx); + return 0; } -- 1.7.11.7
On Thu, 2013-04-11 at 16:01 +0900, Namhyung Kim wrote: > From: Namhyung Kim <namhyung.kim@lge.com> > > The ftrace_graph_count can be decreased with a "!" pattern, so that > the enabled flag should be updated too. Thanks! Once again I'll push patch 1 to 3.9 and stable as that's a nasty bug. But this patch isn't that big of a deal, and as we are in the later -rc's I'll label it with stable and add it to the 3.10 queue. Thanks, -- Steve > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > --- > kernel/trace/ftrace.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index be2bcb7ab2f7..daf8df20b764 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -3779,7 +3779,8 @@ out: > if (fail) > return -EINVAL; > > - ftrace_graph_filter_enabled = 1; > + ftrace_graph_filter_enabled = !!(*idx); > + > return 0; > } >
[-- Attachment #1: Type: text/plain, Size: 3750 bytes --] From: Namhyung Kim <namhyung.kim@lge.com> Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- include/linux/ftrace.h | 2 +- kernel/trace/ftrace.c | 10 +++++----- kernel/trace/trace_stack.c | 2 +- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 167abf9..eb3ce32 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -396,7 +396,7 @@ ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos); ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos); -loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence); +loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence); int ftrace_regex_release(struct inode *inode, struct file *file); void __init diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 926ebfb..affc35d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2697,7 +2697,7 @@ ftrace_notrace_open(struct inode *inode, struct file *file) } loff_t -ftrace_regex_lseek(struct file *file, loff_t offset, int whence) +ftrace_filter_lseek(struct file *file, loff_t offset, int whence) { loff_t ret; @@ -3570,7 +3570,7 @@ static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3578,7 +3578,7 @@ static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; @@ -3783,8 +3783,8 @@ static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, + .llseek = ftrace_filter_lseek, .release = ftrace_graph_release, - .llseek = seq_lseek, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ @@ -4439,7 +4439,7 @@ static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, - .llseek = seq_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_pid_release, }; diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 42ca822..83a8b5b 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -322,7 +322,7 @@ static const struct file_operations stack_trace_filter_fops = { .open = stack_trace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = ftrace_filter_lseek, .release = ftrace_regex_release, }; -- 1.7.10.4 [-- Attachment #2: This is a digitally signed message part --] [-- Type: application/pgp-signature, Size: 490 bytes --]