diff options
| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-12-15 16:41:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-20 19:00:28 +0300 |
| commit | 869aee35cf61392c63fdeb153ced3da962a224cf (patch) | |
| tree | daf74c0b21d23c82759f29f030d9bae1b47723de | |
| parent | c425a772fc58f051f5c8bb01931a4ae3845056b3 (diff) | |
| download | linux-869aee35cf61392c63fdeb153ced3da962a224cf.tar.xz | |
ring-buffer: Have rb_time_cmpxchg() set the msb counter too
commit 0aa0e5289cfe984a8a9fdd79ccf46ccf080151f7 upstream.
The rb_time_cmpxchg() on 32-bit architectures requires setting three
32-bit words to represent the 64-bit timestamp, with some salt for
synchronization. Those are: msb, top, and bottom
The issue is, the rb_time_cmpxchg() did not properly salt the msb portion,
and the msb that was written was stale.
Link: https://lore.kernel.org/linux-trace-kernel/20231215084114.20899342@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: f03f2abce4f39 ("ring-buffer: Have 32 bit time stamps use all 64 bits")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 7c1510c9c456..61803208706a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -727,10 +727,12 @@ static int rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set) cnt2 = cnt + 1; rb_time_split(val, &top, &bottom, &msb); + msb = rb_time_val_cnt(msb, cnt); top = rb_time_val_cnt(top, cnt); bottom = rb_time_val_cnt(bottom, cnt); rb_time_split(set, &top2, &bottom2, &msb2); + msb2 = rb_time_val_cnt(msb2, cnt); top2 = rb_time_val_cnt(top2, cnt2); bottom2 = rb_time_val_cnt(bottom2, cnt2); |