linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2020-01-02	tracing: Initialize val to zero in parse_entry of inject code	Steven Rostedt (VMware)	1	-1/+1
	gcc produces a variable may be uninitialized warning for "val" in parse_entry(). This is really a false positive, but the code is subtle enough to just initialize val to zero and it's not a fast path to worry about it. Marked for stable to remove the warning in the stable trees as well. Cc: stable@vger.kernel.org Fixes: 6c3edaf9fd6a3 ("tracing: Introduce trace event injection") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-12-10	tracing: remove set but not used variable 'buffer'	YueHaibing	1	-2/+0
	kernel/trace/trace_events_inject.c: In function trace_inject_entry: kernel/trace/trace_events_inject.c:20:22: warning: variable buffer set but not used [-Wunused-but-set-variable] It is never used, so remove it. Link: http://lkml.kernel.org/r/20191207034409.25668-1-yuehaibing@huawei.com Reported-by: Hulk Robot <hulkci@huawei.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-12-02	tracing: Introduce trace event injection	Cong Wang	1	-0/+331
	We have been trying to use rasdaemon to monitor hardware errors like correctable memory errors. rasdaemon uses trace events to monitor various hardware errors. In order to test it, we have to inject some hardware errors, unfortunately not all of them provide error injections. MCE does provide a way to inject MCE errors, but errors like PCI error and devlink error don't, it is not easy to add error injection to each of them. Instead, it is relatively easier to just allow users to inject trace events in a generic way so that all trace events can be injected. This patch introduces trace event injection, where a new 'inject' is added to each tracepoint directory. Users could write into this file with key=value pairs to specify the value of each fields of the trace event, all unspecified fields are set to zero values by default. For example, for the net/net_dev_queue tracepoint, we can inject: INJECT=/sys/kernel/debug/tracing/events/net/net_dev_queue/inject echo "" > $INJECT echo "name='test'" > $INJECT echo "name='test' len=1024" > $INJECT cat /sys/kernel/debug/tracing/trace ... <...>-614 [000] .... 36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0 <...>-614 [001] .... 136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0 <...>-614 [001] .N.. 208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024 Triggers could be triggered as usual too: echo "stacktrace if len == 1025" > /sys/kernel/debug/tracing/events/net/net_dev_queue/trigger echo "len=1025" > $INJECT cat /sys/kernel/debug/tracing/trace ... bash-614 [000] .... 36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0 bash-614 [001] .... 136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0 bash-614 [001] .N.. 208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024 bash-614 [001] .N.1 284.236349: <stack trace> => event_inject_write => vfs_write => ksys_write => do_syscall_64 => entry_SYSCALL_64_after_hwframe The only thing that can't be injected is string pointers as they require constant string pointers, this can't be done at run time. Link: http://lkml.kernel.org/r/20191130045218.18979-1-xiyou.wangcong@gmail.com Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>