On 29/06/2021 18:19, Daniel Bristot de Oliveira wrote: > On 6/29/21 6:52 PM, Colin King wrote: >> From: Colin Ian King <colin.king@xxxxxxxxxxxxx> >> >> The less than zero comparison of the u64 variable 'noise' is always >> false because the variable is unsigned. Since the time_sub macro >> can potentially return an -ve vale, make the variable a s64 to >> fix the issue. > > Ops! concurrent bug fixing. Well, shows static analysis is doing it's thing and I'm not being vigilant enough by spotting that Dan found it earlier :-) > > Dan Carpenter reported the same bug (and another problem), and I was working in > the patches... I saw yours after sending his ones: > > https://lore.kernel.org/lkml/acd7cd6e7d56b798a298c3bc8139a390b3c4ab52.1624986368.git.bristot@xxxxxxxxxx/ > > The patches do the same fix, but there it also: > > - Made also max_noise s64 (it is snapshot of noise). > - Arranged the declarations in the inverted christmas tree. > >> Addresses-Coverity: ("Unsigned compared against 0") >> Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") >> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> > > Steven, can we merge the flags? > > -- Daniel > >> --- >> kernel/trace/trace_osnoise.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c >> index 38aa5e208ffd..02c984560ceb 100644 >> --- a/kernel/trace/trace_osnoise.c >> +++ b/kernel/trace/trace_osnoise.c >> @@ -1040,11 +1040,11 @@ static void osnoise_stop_tracing(void) >> static int run_osnoise(void) >> { >> struct osnoise_variables *osn_var = this_cpu_osn_var(); >> - u64 noise = 0, sum_noise = 0, max_noise = 0; >> + u64 sum_noise = 0, max_noise = 0; >> struct trace_array *tr = osnoise_trace; >> u64 start, sample, last_sample; >> u64 last_int_count, int_count; >> - s64 total, last_total = 0; >> + s64 noise = 0, total, last_total = 0; >> struct osnoise_sample s; >> unsigned int threshold; >> int hw_count = 0; >> >
