From: Ankita Garg Date: Mon, 12 May 2008 19:20:58 +0000 (+0200) Subject: ftrace: fix conversion of task state to char in latency tracer X-Git-Tag: v2.6.27-rc1~1102^2^2~1^2~58 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d17d969160c18b631a19c2b34d260691402650f8;p=linux-2.6 ftrace: fix conversion of task state to char in latency tracer The conversion of task states to a character in the sched_switch tracer (part of latency tracer infrastructure), seems to be incorrect. We currently do it by indexing into the state_to_char array using the state value. The state values do not map directly into the array index and are thus incorrect. The following patch addresses this issue. This is also what is being done even in the show_task() routine in kernel/sched.c The patch has been compile and run tested. Signed-off-by: Ankita Garg Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0eef0503fe..9197782d15 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1208,6 +1208,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) char *comm; int S, T; int i; + unsigned state; if (!next_entry) next_entry = entry; @@ -1238,11 +1239,11 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) break; case TRACE_CTX: case TRACE_WAKE: - S = entry->ctx.prev_state < sizeof(state_to_char) ? - state_to_char[entry->ctx.prev_state] : 'X'; T = entry->ctx.next_state < sizeof(state_to_char) ? state_to_char[entry->ctx.next_state] : 'X'; + state = entry->ctx.prev_state ? __ffs(entry->ctx.prev_state) + 1 : 0; + S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X'; comm = trace_find_cmdline(entry->ctx.next_pid); trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n", entry->ctx.prev_pid,