* Re: WARNING at __ftrace_hash_rec_update()
2011-11-01 14:15 WARNING at __ftrace_hash_rec_update() Rabin Vincent
@ 2011-11-05 0:31 ` Steven Rostedt
2011-11-11 10:14 ` Rabin Vincent
2011-11-18 23:14 ` [tip:perf/core] ftrace: Fix hash record accounting bug tip-bot for Steven Rostedt
2011-12-06 6:29 ` tip-bot for Steven Rostedt
2 siblings, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2011-11-05 0:31 UTC (permalink / raw)
To: Rabin Vincent; +Cc: linux-kernel
On Tue, 2011-11-01 at 19:45 +0530, Rabin Vincent wrote:
> On v3.1-7810-g094803e (current linus git), I'm able to trigger the below
> FTRACE_WARN_ON() by running the following sequence of commands.
> DYNAMIC_FTRACE is enabled.
>
> ftrace.c:1384:
> if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
> return;
> rec->flags--;
>
Thanks for reporting. Can you try this patch please.
-- Steve
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0fcc6ca..9af2ea6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1210,7 +1210,8 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
if (!src->count) {
free_ftrace_hash_rcu(*dst);
rcu_assign_pointer(*dst, EMPTY_HASH);
- return 0;
+ /* still need to update the function records */
+ goto out;
}
/*
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: WARNING at __ftrace_hash_rec_update()
2011-11-05 0:31 ` Steven Rostedt
@ 2011-11-11 10:14 ` Rabin Vincent
0 siblings, 0 replies; 5+ messages in thread
From: Rabin Vincent @ 2011-11-11 10:14 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel
On Fri, Nov 04, 2011 at 08:31:34PM -0400, Steven Rostedt wrote:
> On Tue, 2011-11-01 at 19:45 +0530, Rabin Vincent wrote:
> > On v3.1-7810-g094803e (current linus git), I'm able to trigger the below
> > FTRACE_WARN_ON() by running the following sequence of commands.
> > DYNAMIC_FTRACE is enabled.
> >
> > ftrace.c:1384:
> > if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
> > return;
> > rec->flags--;
> >
>
> Thanks for reporting. Can you try this patch please.
Works for me, thanks. It needed a ret=0 which I see you've already
added in your official submission.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [tip:perf/core] ftrace: Fix hash record accounting bug
2011-11-01 14:15 WARNING at __ftrace_hash_rec_update() Rabin Vincent
2011-11-05 0:31 ` Steven Rostedt
@ 2011-11-18 23:14 ` tip-bot for Steven Rostedt
2011-12-06 6:29 ` tip-bot for Steven Rostedt
2 siblings, 0 replies; 5+ messages in thread
From: tip-bot for Steven Rostedt @ 2011-11-18 23:14 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, rabin, rostedt, srostedt, tglx
Commit-ID: d4d34b981a5327eec956c6cb4cce397ce6f57279
Gitweb: http://git.kernel.org/tip/d4d34b981a5327eec956c6cb4cce397ce6f57279
Author: Steven Rostedt <srostedt@redhat.com>
AuthorDate: Fri, 4 Nov 2011 20:32:39 -0400
Committer: Steven Rostedt <rostedt@goodmis.org>
CommitDate: Mon, 7 Nov 2011 13:48:05 -0500
ftrace: Fix hash record accounting bug
If the set_ftrace_filter is cleared by writing just whitespace to
it, then the filter hash refcounts will be decremented but not
updated. This causes two bugs:
1) No functions will be enabled for tracing when they all should be
2) If the users clears the set_ftrace_filter twice, it will crash ftrace:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7()
Modules linked in:
Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32
Call Trace:
[<ffffffff81051828>] warn_slowpath_common+0x83/0x9b
[<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c
[<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7
[<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f
[<ffffffff8111bdfe>] ? kfree+0xe5/0x115
[<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151
[<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f
[<ffffffff8112e49a>] fput+0xfd/0x1c2
[<ffffffff8112b54c>] filp_close+0x6d/0x78
[<ffffffff8113a92d>] sys_dup3+0x197/0x1c1
[<ffffffff8113a9a6>] sys_dup2+0x4f/0x54
[<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b
---[ end trace 77a3a7ee73794a02 ]---
Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/ftrace.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0fcc6ca..7caa450 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1210,7 +1210,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
if (!src->count) {
free_ftrace_hash_rcu(*dst);
rcu_assign_pointer(*dst, EMPTY_HASH);
- return 0;
+ /* still need to update the function records */
+ ret = 0;
+ goto out;
}
/*
^ permalink raw reply related [flat|nested] 5+ messages in thread* [tip:perf/core] ftrace: Fix hash record accounting bug
2011-11-01 14:15 WARNING at __ftrace_hash_rec_update() Rabin Vincent
2011-11-05 0:31 ` Steven Rostedt
2011-11-18 23:14 ` [tip:perf/core] ftrace: Fix hash record accounting bug tip-bot for Steven Rostedt
@ 2011-12-06 6:29 ` tip-bot for Steven Rostedt
2 siblings, 0 replies; 5+ messages in thread
From: tip-bot for Steven Rostedt @ 2011-12-06 6:29 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, rabin, rostedt, srostedt, tglx
Commit-ID: ddf6e0e50723b62ac76ed18eb53e9417c6eefba7
Gitweb: http://git.kernel.org/tip/ddf6e0e50723b62ac76ed18eb53e9417c6eefba7
Author: Steven Rostedt <srostedt@redhat.com>
AuthorDate: Fri, 4 Nov 2011 20:32:39 -0400
Committer: Steven Rostedt <rostedt@goodmis.org>
CommitDate: Mon, 5 Dec 2011 13:28:47 -0500
ftrace: Fix hash record accounting bug
If the set_ftrace_filter is cleared by writing just whitespace to
it, then the filter hash refcounts will be decremented but not
updated. This causes two bugs:
1) No functions will be enabled for tracing when they all should be
2) If the users clears the set_ftrace_filter twice, it will crash ftrace:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7()
Modules linked in:
Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32
Call Trace:
[<ffffffff81051828>] warn_slowpath_common+0x83/0x9b
[<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c
[<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7
[<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f
[<ffffffff8111bdfe>] ? kfree+0xe5/0x115
[<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151
[<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f
[<ffffffff8112e49a>] fput+0xfd/0x1c2
[<ffffffff8112b54c>] filp_close+0x6d/0x78
[<ffffffff8113a92d>] sys_dup3+0x197/0x1c1
[<ffffffff8113a9a6>] sys_dup2+0x4f/0x54
[<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b
---[ end trace 77a3a7ee73794a02 ]---
Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/ftrace.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1276b3c..b1e8943 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1211,7 +1211,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
if (!src->count) {
free_ftrace_hash_rcu(*dst);
rcu_assign_pointer(*dst, EMPTY_HASH);
- return 0;
+ /* still need to update the function records */
+ ret = 0;
+ goto out;
}
/*
^ permalink raw reply related [flat|nested] 5+ messages in thread