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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-02-02 14:03:39 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-02-03 10:59:06 -0500 |
| commit | d4ad9a1ccac31a04a32b5e7547b70428830e0218 (patch) | |
| tree | 9a5819bc82212f3b38382cb4aa8cc173f0c30e10 /kernel/trace | |
| parent | 555fc7813eeada1738eca42aa9f9ebafd7dc23e6 (diff) | |
| download | op-kernel-dev-d4ad9a1ccac31a04a32b5e7547b70428830e0218.zip op-kernel-dev-d4ad9a1ccac31a04a32b5e7547b70428830e0218.tar.gz | |
ftrace: Reset fgd->hash in ftrace_graph_write()
fgd->hash is saved and then freed, but is never reset to either
ftrace_graph_hash nor ftrace_graph_notrace_hash. But if multiple writes 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 ]---
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/ftrace.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a9cfc87..b7df0dc 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); |
