kernel/linux.git/tools/tracing/rtla/src/common.c, branch v7.0.13

rtla: Fix parsing of multi-character short options

2026-06-19T11:47:49+00:00

[ Upstream commit e9e41d3035032ed6053d8bad7b7077e1cb3a6540 ] A bug was reported where the parsing of multi-character short options, be it a short option with an argument specified without space (e.g. "-p100") or multiple short options in one argument (e.g. -un), ignores options specific to individual tools. Furthermore, if the rest of the option is supposed to be an argument, it gets reinterpreted as a string of options. For example, -p100 gets interpreted as -100, which is due to hackish implementation read as --no-thread --no-irq --no-irq with timerlat hist, causing rtla to error out: $ rtla timerlat hist -p100 no-irq and no-thread set, there is nothing to do here This behavior is caused by getopt_long() being called twice on each argument, once in common_parse_options(), once in [tool]_parse_args(): - common_parse_options() calls getopt_long() with an array of options common for all rtla tools, while suppressing errors (opterr = 0). - If the option fails to parse, common_parse_options() returns 0. - If 0 is returned from common_parse_options(), [tool]_parse_args() calls getopt_long() again, with its own set of options. * [tool] means one of {osnoise,timerlat}_{top,hist} At least in glibc, getopt_long() increments its internal nextchar variable even if the option is not recognized. That means that in the case of "-p100", common_parse_options() sets nextchar pointing to '1', and timerlat_hist_parse_args() sees '1', not 'p'; the same then repeats for the first and second '0'. As there is no way to restore the correct internal state of getopt_long() reliably, fix the issue by merging the common options back to the longopt array and option string of the [tool]_parse_args() functions using a macro; only the switch part is left in the original function, which is renamed to set_common_option(). Fixes: 850cd24cb6d6 ("tools/rtla: Add common_parse_options()") Reported-by: John Kacur Tested-by: John Kacur Link: https://lore.kernel.org/r/20260602125506.3325345-1-tglozar@redhat.com Signed-off-by: Tomas Glozar Signed-off-by: Sasha Levin

rtla: Fix segfault on multiple SIGINTs

2026-05-23T11:08:56+00:00

[ Upstream commit be8058f31b4e237604e4ce7599593ab68dc69ae7 ] Detach stop_trace() from SIGINT/SIGALRM on tool clean-up to prevent it from crashing RTLA by accessing freed memory. This prevents a crash when multiple SIGINTs are received. Fixes: d6899e560366 ("rtla/timerlat_hist: Abort event processing on second signal") Fixes: 80967b354a76 ("rtla/timerlat_top: Abort event processing on second signal") Reviewed-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260310160725.144443-1-tglozar@redhat.com Signed-off-by: Tomas Glozar Signed-off-by: Sasha Levin

tools/rtla: Generate optstring from long options

2026-05-23T11:08:56+00:00

[ Upstream commit 4a1cec7450b7159a0ee57403f44460ac4d618b4f ] getopt_long() processes short and long options independently. RTLA, like the majority of applications, uses both short and long variants for each logical option. Since the val member of struct option holds the letter of the short variant, the string of short options can be reconstructed from the array of long options. Add getopt_auto() to generate optstring from an array of long options, eliminating the need to maintain separate short option strings. Signed-off-by: Costa Shulyupin Reviewed-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260108095011.2115719-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar Stable-dep-of: be8058f31b4e ("rtla: Fix segfault on multiple SIGINTs") Signed-off-by: Sasha Levin

rtla: Make stop_tracing variable volatile

2026-01-07T14:57:55+00:00

The stop_tracing global variable is accessed from both the signal handler context and the main program flow without synchronization. This creates a potential race condition where compiler optimizations could cache the variable value in registers, preventing the signal handler's updates from being visible to other parts of the program. Add the volatile qualifier to stop_tracing in both common.c and common.h to ensure all accesses to this variable bypass compiler optimizations and read directly from memory. This guarantees that when the signal handler sets stop_tracing, the change is immediately visible to the main program loop, preventing potential hangs or delayed shutdown when termination signals are received. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260106133655.249887-16-wander@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -H/--house-keeping option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -H/--house-keeping. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-8-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -P/--priority option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -P/--priority. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-7-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -e/--event option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -e/--event. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-6-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -d/--duration option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -d/--duration. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-5-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -D/--debug option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -D/--debug. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-4-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate -C/--cgroup option parsing

2026-01-07T14:57:17+00:00

Each rtla tool duplicates parsing of -C/--cgroup. Migrate the option parsing from individual tools to the common_parse_options(). Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20251209100047.2692515-3-costa.shul@redhat.com Signed-off-by: Tomas Glozar