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SubjectRe: [tip:tracing/ftrace] tracing: fix oops in tracepoint_update_probe_range()
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On Wed, 2009-03-18 at 17:51 +0000, Jaswinder Singh Rajput wrote:
> Commit-ID: 966a6fdf6210e3ac8ce00b61cd1107cdf97ce744
> Gitweb: http://git.kernel.org/tip/966a6fdf6210e3ac8ce00b61cd1107cdf97ce744
> Author: Jaswinder Singh Rajput <jaswinder@kernel.org>
> AuthorDate: Wed, 18 Mar 2009 22:18:56 +0530
> Commit: Ingo Molnar <mingo@elte.hu>
> CommitDate: Wed, 18 Mar 2009 18:48:43 +0100
>
> tracing: fix oops in tracepoint_update_probe_range()
>
> Change this crash:
>
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffff8107d4de>] tracepoint_update_probe_range+0x1f/0x9b
> PGD 13d5fb067 PUD 13d688067 PMD 0
> Oops: 0000 [#1] SMP
>
> To a more debuggable WARN_ONCE().
>
> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> LKML-Reference: <1237394936.3132.1.camel@localhost.localdomain>
> [ moved the check outside the lock and added a WARN_ON(). ]
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
>
> ---
> kernel/tracepoint.c | 9 +++++++--
> 1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index 7960274..dd15df9 100644
> --- a/kernel/tracepoint.c
> +++ b/kernel/tracepoint.c
> @@ -272,12 +272,17 @@ static void disable_tracepoint(struct tracepoint *elem)
> *
> * Updates the probe callback corresponding to a range of tracepoints.
> */
> -void tracepoint_update_probe_range(struct tracepoint *begin,
> - struct tracepoint *end)
> +void
> +tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
> {
> struct tracepoint *iter;
> struct tracepoint_entry *mark_entry;
>
> + if (!iter) {
> + WARN_ON_ONCE(1);
> + return;
> + }
> +
> mutex_lock(&tracepoints_mutex);
> for (iter = begin; iter < end; iter++) {
> mark_entry = get_tracepoint(iter->name);

my original patch was correct.

--
JSR




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