kernel/include/linux/tracepoint.h, branch linux-5.11.y

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

tracepoint: Use __used attribute definitions from compiler_attributes.h

2020-08-03T17:34:37Z

Just a small cleanup while I was touching this header. compiler_attributes.h does feature detection of these __attributes__(()) and provides more concise ways to invoke them. Link: https://lkml.kernel.org/r/20200730224555.2142154-3-ndesaulniers@google.com Acked-by: Miguel Ojeda Signed-off-by: Nick Desaulniers Signed-off-by: Steven Rostedt (VMware)

tracepoint: Mark __tracepoint_string's __used

2020-08-03T17:34:04Z

__tracepoint_string's have their string data stored in .rodata, and an address to that data stored in the "__tracepoint_str" section. Functions that refer to those strings refer to the symbol of the address. Compiler optimization can replace those address references with references directly to the string data. If the address doesn't appear to have other uses, then it appears dead to the compiler and is removed. This can break the /tracing/printk_formats sysfs node which iterates the addresses stored in the "__tracepoint_str" section. Like other strings stored in custom sections in this header, mark these __used to inform the compiler that there are other non-obvious users of the address, so they should still be emitted. Link: https://lkml.kernel.org/r/20200730224555.2142154-2-ndesaulniers@google.com Cc: Ingo Molnar Cc: Miguel Ojeda Cc: stable@vger.kernel.org Fixes: 102c9323c35a8 ("tracing: Add __tracepoint_string() to export string pointers") Reported-by: Tim Murray Reported-by: Simon MacMullen Suggested-by: Greg Hackmann Signed-off-by: Nick Desaulniers Signed-off-by: Steven Rostedt (VMware)

tracing: Remove DECLARE_TRACE_NOARGS

2020-04-23T02:06:35Z

This macro was intentionally broken so that the kernel code is not poluted with such noargs macro used simply as markers. This use case can be satisfied by using dummy no inline functions. Just remove it. Link: http://lkml.kernel.org/r/20200413153246.8511-1-nborisov@suse.com Signed-off-by: Nikolay Borisov Signed-off-by: Steven Rostedt (VMware)

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 365

2019-06-05T15:37:09Z

Based on 1 normalized pattern(s): this file is released under the gplv2 see the file copying for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Armijn Hemel Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531081035.872590698@linutronix.de Signed-off-by: Greg Kroah-Hartman

tracing: introduce TRACE_EVENT_NOP()

2019-04-08T13:22:51Z

Sometimes we want to define a tracepoint as a do-nothing function. So I introduce TRACE_EVENT_NOP, DECLARE_EVENT_CLASS_NOP and DEFINE_EVENT_NOP for this kind of usage. Link: http://lkml.kernel.org/r/1553602391-11926-2-git-send-email-laoar.shao@gmail.com Signed-off-by: Yafang Shao Signed-off-by: Steven Rostedt (VMware)

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

2018-12-04T06:52:30Z

Pull RCU changes from Paul E. McKenney: - Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar. - Replace calls of RCU-bh and RCU-sched update-side functions to their vanilla RCU counterparts. This series is a step towards complete removal of the RCU-bh and RCU-sched update-side functions. ( Note that some of these conversions are going upstream via their respective maintainers. ) - Documentation updates, including a number of flavor-consolidation updates from Joel Fernandes. - Miscellaneous fixes. - Automate generation of the initrd filesystem used for rcutorture testing. - Convert spin_is_locked() assertions to instead use lockdep. ( Note that some of these conversions are going upstream via their respective maintainers. ) - SRCU updates, especially including a fix from Dennis Krein for a bag-on-head-class bug. - RCU torture-test updates. Signed-off-by: Ingo Molnar