https://github.com/torvalds/linux
Revision 71c7a30442b724717a30d5e7d1662ba4904eb3d4 authored by Costa Shulyupin on 16 March 2023, 14:45:35 UTC, committed by Steven Rostedt (Google) on 19 March 2023, 17:23:22 UTC
There is a problem with the behavior of hwlat in a container, resulting in incorrect output. A warning message is generated: "cpumask changed while in round-robin mode, switching to mode none", and the tracing_cpumask is ignored. This issue arises because the kernel thread, hwlatd, is not a part of the container, and the function sched_setaffinity is unable to locate it using its PID. Additionally, the task_struct of hwlatd is already known. Ultimately, the function set_cpus_allowed_ptr achieves the same outcome as sched_setaffinity, but employs task_struct instead of PID. Test case: # cd /sys/kernel/tracing # echo 0 > tracing_on # echo round-robin > hwlat_detector/mode # echo hwlat > current_tracer # unshare --fork --pid bash -c 'echo 1 > tracing_on' # dmesg -c Actual behavior: [573502.809060] hwlat_detector: cpumask changed while in round-robin mode, switching to mode none Link: https://lore.kernel.org/linux-trace-kernel/20230316144535.1004952-1-costa.shul@redhat.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 0330f7aa8ee63 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Tip revision: 71c7a30442b724717a30d5e7d1662ba4904eb3d4 authored by Costa Shulyupin on 16 March 2023, 14:45:35 UTC
tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr
tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr
Tip revision: 71c7a30
File | Mode | Size |
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LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 20.0 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 151 bytes |
.gitattributes | -rw-r--r-- | 62 bytes |
.gitignore | -rw-r--r-- | 2.0 KB |
.mailmap | -rw-r--r-- | 24.8 KB |
.rustfmt.toml | -rw-r--r-- | 369 bytes |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 99.3 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 681.8 KB |
Makefile | -rw-r--r-- | 70.2 KB |
README | -rw-r--r-- | 727 bytes |
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