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authorQiujun Huang <hqjagain@gmail.com>2020-10-29 19:19:05 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-11-02 16:52:18 +0300
commitc1acb4ac1a892cf08d27efcb964ad281728b0545 (patch)
treee71d042cd9413d49fa129ca0091e8d54b64f8639 /kernel
parent3cea11cd5e3b00d91caf0b4730194039b45c5891 (diff)
downloadlinux-c1acb4ac1a892cf08d27efcb964ad281728b0545.tar.xz
tracing: Fix out of bounds write in get_trace_buf
The nesting count of trace_printk allows for 4 levels of nesting. The nesting counter starts at zero and is incremented before being used to retrieve the current context's buffer. But the index to the buffer uses the nesting counter after it was incremented, and not its original number, which in needs to do. Link: https://lkml.kernel.org/r/20201029161905.4269-1-hqjagain@gmail.com Cc: stable@vger.kernel.org Fixes: 3d9622c12c887 ("tracing: Add barrier to trace_printk() buffer nesting modification") Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 528971714fc6..daa96215e294 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3132,7 +3132,7 @@ static char *get_trace_buf(void)
/* Interrupts must see nesting incremented before we use the buffer */
barrier();
- return &buffer->buffer[buffer->nesting][0];
+ return &buffer->buffer[buffer->nesting - 1][0];
}
static void put_trace_buf(void)