From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Namhyung Kim <namhyung@kernel.org>
Subject: [for-next][PATCH 4/8] ftrace: Reset fgd->hash in ftrace_graph_write()
Date: Fri, 03 Feb 2017 08:40:37 -0500 [thread overview]
Message-ID: <20170203134137.170783029@goodmis.org> (raw)
In-Reply-To: 20170203134033.087760237@goodmis.org
[-- Attachment #1: 0004-ftrace-Reset-fgd-hash-in-ftrace_graph_write.patch --]
[-- Type: text/plain, Size: 2701 bytes --]
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
fgd->hash is saved and then freed, but is never reset to either
ftrace_graph_hash nor ftrace_graph_notrace_hash. But if multiple reads are
performed, then the freed hash could be accessed again.
# cd /sys/kernel/debug/tracing
# head -1000 available_filter_functions > /tmp/funcs
# cat /tmp/funcs > set_graph_function
Causes:
general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: [...]
CPU: 2 PID: 1337 Comm: cat Not tainted 4.10.0-rc2-test-00010-g6b052e9 #32
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
task: ffff880113a12200 task.stack: ffffc90001940000
RIP: 0010:free_ftrace_hash+0x7c/0x160
RSP: 0018:ffffc90001943db0 EFLAGS: 00010246
RAX: 6b6b6b6b6b6b6b6b RBX: 6b6b6b6b6b6b6b6b RCX: 6b6b6b6b6b6b6b6b
RDX: 0000000000000002 RSI: 0000000000000001 RDI: ffff8800ce1e1d40
RBP: ffff8800ce1e1d50 R08: 0000000000000000 R09: 0000000000006400
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8800ce1e1d40 R14: 0000000000004000 R15: 0000000000000001
FS: 00007f9408a07740(0000) GS:ffff88011e500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000aee1f0 CR3: 0000000116bb4000 CR4: 00000000001406e0
Call Trace:
? ftrace_graph_write+0x150/0x190
? __vfs_write+0x1f6/0x210
? __audit_syscall_entry+0x17f/0x200
? rw_verify_area+0xdb/0x210
? _cond_resched+0x2b/0x50
? __sb_start_write+0xb4/0x130
? vfs_write+0x1c8/0x330
? SyS_write+0x62/0xf0
? do_syscall_64+0xa3/0x1b0
? entry_SYSCALL64_slow_path+0x25/0x25
Code: 01 48 85 db 0f 84 92 00 00 00 b8 01 00 00 00 d3 e0 85 c0 7e 3f 83 e8 01 48 8d 6f 10 45 31 e4 4c 8d 34 c5 08 00 00 00 49 8b 45 08 <4a> 8b 34 20 48 85 f6 74 13 48 8b 1e 48 89 ef e8 20 fa ff ff 48
RIP: free_ftrace_hash+0x7c/0x160 RSP: ffffc90001943db0
---[ end trace 999b48216bf4b393 ]---
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/ftrace.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a9cfc8713198..b7df0dcf8652 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4858,10 +4858,13 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
if (!new_hash)
ret = -ENOMEM;
- if (fgd->type == GRAPH_FILTER_FUNCTION)
+ if (fgd->type == GRAPH_FILTER_FUNCTION) {
rcu_assign_pointer(ftrace_graph_hash, new_hash);
- else
+ fgd->hash = ftrace_graph_hash;
+ } else {
rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
+ fgd->hash = ftrace_graph_notrace_hash;
+ }
mutex_unlock(&graph_lock);
--
2.10.2
next prev parent reply other threads:[~2017-02-03 13:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-03 13:40 [for-next][PATCH 0/8] tracing: Clean up hash logic for set_graph_function Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 1/8] tracing: Add ftrace_hash_key() helper function Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 2/8] ftrace: Create a slight optimization on searching the ftrace_hash Steven Rostedt
2017-02-03 14:26 ` Namhyung Kim
2017-02-03 14:57 ` Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 3/8] ftrace: Replace (void *)1 with a meaningful macro name FTRACE_GRAPH_EMPTY Steven Rostedt
2017-02-03 13:40 ` Steven Rostedt [this message]
2017-02-03 14:49 ` [for-next][PATCH 4/8] ftrace: Reset fgd->hash in ftrace_graph_write() Namhyung Kim
2017-02-03 14:57 ` Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 5/8] ftrace: Have set_graph_functions handle write with RDWR Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 6/8] tracing: Reset parser->buffer to allow multiple "puts" Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 7/8] ftrace: Do not hold references of ftrace_graph_{notrace_}hash out of graph_lock Steven Rostedt
2017-02-03 13:40 ` [for-next][PATCH 8/8] ftrace: Have set_graph_function handle multiple functions in one write Steven Rostedt
2017-02-03 15:14 ` [for-next][PATCH 0/8] tracing: Clean up hash logic for set_graph_function Namhyung Kim
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170203134137.170783029@goodmis.org \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=namhyung@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.