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| author |   Jason A. Donenfeld <Jason@zx2c4.com> | 2019-03-18 12:49:25 -0600 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2019-03-18 12:50:00 -0600 |
| commit | 51822f722a033a481a5e0edcc51e33f5c39e9369 (patch) | |
| tree | 8c1beb370602550b4736b5858f47d49c76eaa423 /WireGuard/Shared/Logging/ringlogger.c | |
| parent | macOS: Tunnels list: Double-click to activate / deactivate (diff) | |
| download | wireguard-apple-51822f722a033a481a5e0edcc51e33f5c39e9369.tar.xz wireguard-apple-51822f722a033a481a5e0edcc51e33f5c39e9369.zip | |
ringlogger: document races
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'WireGuard/Shared/Logging/ringlogger.c')
| -rw-r--r-- | WireGuard/Shared/Logging/ringlogger.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/WireGuard/Shared/Logging/ringlogger.c b/WireGuard/Shared/Logging/ringlogger.c index 440a269..563483a 100644 --- a/WireGuard/Shared/Logging/ringlogger.c +++ b/WireGuard/Shared/Logging/ringlogger.c @@ -42,11 +42,14 @@ void write_msg_to_log(struct log *log, const char *tag, const char *msg) struct log_line *line; struct timespec ts; + // Race: This isn't synchronized with the fetch_add below, so items might be slightly out of order. clock_gettime(CLOCK_REALTIME, &ts); + // Race: More than MAX_LINES writers and this will clash. index = atomic_fetch_add(&log->next_index, 1); line = &log->lines[index % MAX_LINES]; + // Race: Before this line executes, we'll display old data after new data. atomic_store(&line->time_ns, 0); memset(line->line, 0, MAX_LOG_LINE_LENGTH); |