user/sven/linux.git/include/linux/tracepoint.h, branch v5.16.19

tracing: Fix a typo in tracepoint.h

2021-08-16T15:37:21Z

It should be @prev_pid, not @prev_prid. Link: https://lkml.kernel.org/r/20210802140234.5383-1-shijie@os.amperecomputing.com Signed-off-by: Huang Shijie Signed-off-by: Steven Rostedt (VMware)

tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing

2021-06-29T15:51:25Z

All internal use cases for tracepoint_probe_register() is set to not ever be called with the same function and data. If it is, it is considered a bug, as that means the accounting of handling tracepoints is corrupted. If the function and data for a tracepoint is already registered when tracepoint_probe_register() is called, it will call WARN_ON_ONCE() and return with EEXISTS. The BPF system call can end up calling tracepoint_probe_register() with the same data, which now means that this can trigger the warning because of a user space process. As WARN_ON_ONCE() should not be called because user space called a system call with bad data, there needs to be a way to register a tracepoint without triggering a warning. Enter tracepoint_probe_register_may_exist(), which can be called, but will not cause a WARN_ON() if the probe already exists. It will still error out with EEXIST, which will then be sent to the user space that performed the BPF system call. This keeps the previous testing for issues with other users of the tracepoint code, while letting BPF call it with duplicated data and not warn about it. Link: https://lore.kernel.org/lkml/20210626135845.4080-1-penguin-kernel@I-love.SAKURA.ne.jp/ Link: https://syzkaller.appspot.com/bug?id=41f4318cf01762389f4d1c1c459da4f542fe5153 Cc: stable@vger.kernel.org Fixes: c4f6699dfcb85 ("bpf: introduce BPF_RAW_TRACEPOINT") Reported-by: syzbot Reported-by: Tetsuo Handa Tested-by: syzbot+721aa903751db87aa244@syzkaller.appspotmail.com Signed-off-by: Steven Rostedt (VMware)

tracing: Fix various typos in comments

2021-03-23T18:08:18Z

Fix ~59 single-word typos in the tracing code comments, and fix the grammar in a handful of places. Link: https://lore.kernel.org/r/20210322224546.GA1981273@gmail.com Link: https://lkml.kernel.org/r/20210323174935.GA4176821@gmail.com Reviewed-by: Randy Dunlap Signed-off-by: Ingo Molnar Signed-off-by: Steven Rostedt (VMware)

tracepoints: Code clean up

2021-02-09T17:27:29Z

Restructure the code a bit to make it simpler, fix some formatting problems and add READ_ONCE/WRITE_ONCE to make sure there's no compiler load/store tearing to the variables that can be accessed across CPUs. Started with Mathieu Desnoyers's patch: Link: https://lore.kernel.org/lkml/20210203175741.20665-1-mathieu.desnoyers@efficios.com/ And will keep his signature, but I will take the responsibility of this being correct, and keep the authorship. Link: https://lkml.kernel.org/r/20210204143004.61126582@gandalf.local.home Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (VMware)

tracepoints: Do not punish non static call users

2021-02-09T17:16:27Z

With static calls, a tracepoint can call the callback directly if there is only one callback registered to that tracepoint. When there is more than one, the static call will call the tracepoint's "iterator" function, which needs to reload the tracepoint's "funcs" array again, as it could have changed since the first time it was loaded. But an arch without static calls is punished by having to load the tracepoint's "funcs" array twice. Once in the DO_TRACE macro, and once again in the iterator macro. For archs without static calls, there's no reason to load the array macro in the first place, since the iterator function will do it anyway. Change the __DO_TRACE_CALL() macro to do the load and call of the tracepoints funcs array only for architectures with static calls, and just call the iterator function directly for architectures without static calls. Link: https://lkml.kernel.org/r/20210208201050.909329787@goodmis.org Acked-by: Peter Zijlstra (Intel) Signed-off-by: Steven Rostedt (VMware)

tracepoints: Remove unnecessary "data_args" macro parameter

2021-02-09T17:16:27Z

While working on a clean up that would restructure the difference between architectures that have static calls vs those that do not, I was stumbling over the "data_args" parameter that includes "__data" in the arguments. The issue was that one version didn't even need it, while the other one did. Instead of injecting a "__data = NULL;" into the macro for the unneeded version, just remove it completely. The original idea behind data_args is that there may be a case of a tracepoint with no arguments. But this is considered bad practice, and all tracepoints should pass something to that location (that's what tracepoints were created for). Link: https://lkml.kernel.org/r/20210208201050.768074128@goodmis.org Acked-by: Peter Zijlstra (Intel) Signed-off-by: Steven Rostedt (VMware)

tracepoint: Fix race between tracing and removing tracepoint

2021-02-02T14:32:02Z

When executing a tracepoint, the tracepoint's func is dereferenced twice - in __DO_TRACE() (where the returned pointer is checked) and later on in __traceiter_##_name where the returned pointer is dereferenced without checking which leads to races against tracepoint_removal_sync() and crashes. This adds a check before referencing the pointer in tracepoint_ptr_deref. Link: https://lkml.kernel.org/r/20210202072326.120557-1-aik@ozlabs.ru Cc: stable@vger.kernel.org Fixes: d25e37d89dd2f ("tracepoint: Optimize using static_call()") Acked-by: Peter Zijlstra (Intel) Signed-off-by: Alexey Kardashevskiy Signed-off-by: Steven Rostedt (VMware)

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49Z

Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

tracepoint: Fix overly long tracepoint names

2020-09-08T12:10:59Z

Stephen Rothwell reported: > Exported symbols need to be <= (64 - sizeof(Elf_Addr)) long. This is > presumably 56 on 64 bit arches and the above symbol (including the '.') > is 56 characters long. Shorten the tracepoint symbol name. Fixes: d25e37d89dd2 ("tracepoint: Optimize using static_call()") Reported-by: Stephen Rothwell Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200908105743.GW2674@hirez.programming.kicks-ass.net

tracepoint: Optimize using static_call()

2020-09-01T07:58:06Z

Currently the tracepoint site will iterate a vector and issue indirect calls to however many handlers are registered (ie. the vector is long). Using static_call() it is possible to optimize this for the common case of only having a single handler registered. In this case the static_call() can directly call this handler. Otherwise, if the vector is longer than 1, call a function that iterates the whole vector like the current code. [peterz: updated to new interface] Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20200818135805.279421092@infradead.org