user/sven/linux.git/kernel/trace/ftrace.c, branch v5.9.8

ftrace: Move RCU is watching check after recursion check

2020-09-29T17:05:10Z

The first thing that the ftrace function callback helper functions should do is to check for recursion. Peter Zijlstra found that when "rcu_is_watching()" had its notrace removed, it caused perf function tracing to crash. This is because the call of rcu_is_watching() is tested before function recursion is checked and and if it is traced, it will cause an infinite recursion loop. rcu_is_watching() should still stay notrace, but to prevent this should never had crashed in the first place. The recursion prevention must be the first thing done in callback functions. Link: https://lore.kernel.org/r/20200929112541.GM2628@hirez.programming.kicks-ass.net Cc: stable@vger.kernel.org Cc: Paul McKenney Fixes: c68c0fa293417 ("ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too") Acked-by: Peter Zijlstra (Intel) Reported-by: Peter Zijlstra (Intel) Signed-off-by: Steven Rostedt (VMware)

ftrace: Let ftrace_enable_sysctl take a kernel pointer buffer

2020-09-18T17:15:56Z

Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") changed ctl_table.proc_handler to take a kernel pointer. Adjust the signature of ftrace_enable_sysctl to match ctl_table.proc_handler which fixes the following sparse warning: kernel/trace/ftrace.c:7544:43: warning: incorrect type in argument 3 (different address spaces) kernel/trace/ftrace.c:7544:43: expected void * kernel/trace/ftrace.c:7544:43: got void [noderef] __user *buffer Link: https://lkml.kernel.org/r/20200907093207.13540-1-tklauser@distanz.ch Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Cc: Andrew Morton Cc: Ingo Molnar Cc: Christoph Hellwig Cc: Al Viro Signed-off-by: Tobias Klauser Signed-off-by: Steven Rostedt (VMware)

ftrace: Fix missing synchronize_rcu() removing trampoline from kallsyms

2020-09-18T16:22:42Z

Add synchronize_rcu() after list_del_rcu() in ftrace_remove_trampoline_from_kallsyms() to protect readers of ftrace_ops_trampoline_list (in ftrace_get_trampoline_kallsym) which is used when kallsyms is read. Link: https://lkml.kernel.org/r/20200901091617.31837-1-adrian.hunter@intel.com Fixes: fc0ea795f53c8d ("ftrace: Add symbols for ftrace trampolines") Signed-off-by: Adrian Hunter Signed-off-by: Steven Rostedt (VMware)

ftrace: Free the trampoline when ftrace_startup() fails

2020-09-18T16:19:08Z

Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines") missed to remove ops from new ftrace_ops_trampoline_list in ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may lead to BUG if such ops come from a module which may be removed. Moreover, the trampoline itself is not freed in this case. Fix it by calling ftrace_trampoline_free() during the rollback. Link: https://lkml.kernel.org/r/20200831122631.28057-1-mbenes@suse.cz Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines") Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict") Signed-off-by: Miroslav Benes Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-08-08T01:29:15Z

Pull tracing updates from Steven Rostedt: - The biggest news in that the tracing ring buffer can now time events that interrupted other ring buffer events. Before this change, if an interrupt came in while recording another event, and that interrupt also had an event, those events would all have the same time stamp as the event it interrupted. Now, with the new design, those events will have a unique time stamp and rightfully display the time for those events that were recorded while interrupting another event. - Bootconfig how has an "override" operator that lets the users have a default config, but then add options to override the default. - A fix was made to properly filter function graph tracing to the ftrace PIDs. This came in at the end of the -rc cycle, and needs to be backported. - Several clean ups, performance updates, and minor fixes as well. * tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (39 commits) tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE tracing: Use trace_sched_process_free() instead of exit() for pid tracing bootconfig: Fix to find the initargs correctly Documentation: bootconfig: Add bootconfig override operator tools/bootconfig: Add testcases for value override operator lib/bootconfig: Add override operator support kprobes: Remove show_registers() function prototype tracing/uprobe: Remove dead code in trace_uprobe_register() kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler ftrace: Fix ftrace_trace_task return value tracepoint: Use __used attribute definitions from compiler_attributes.h tracepoint: Mark __tracepoint_string's __used trace : Have tracing buffer info use kvzalloc instead of kzalloc tracing: Remove outdated comment in stack handling ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines ftrace: Setup correct FTRACE_FL_REGS flags for module tracing/hwlat: Honor the tracing_cpumask tracing/hwlat: Drop the duplicate assignment in start_kthread() tracing: Save one trace_event->type by using __TRACE_LAST_TYPE ...

tracing: Use trace_sched_process_free() instead of exit() for pid tracing

2020-08-05T00:15:07Z

On exit, if a process is preempted after the trace_sched_process_exit() tracepoint but before the process is done exiting, then when it gets scheduled in, the function tracers will not filter it properly against the function tracing pid filters. That is because the function tracing pid filters hooks to the sched_process_exit() tracepoint to remove the exiting task's pid from the filter list. Because the filtering happens at the sched_switch tracepoint, when the exiting task schedules back in to finish up the exit, it will no longer be in the function pid filtering tables. This was noticeable in the notrace self tests on a preemptable kernel, as the tests would fail as it exits and preempted after being taken off the notrace filter table and on scheduling back in it would not be in the notrace list, and then the ending of the exit function would trace. The test detected this and would fail. Cc: stable@vger.kernel.org Cc: Namhyung Kim Fixes: 1e10486ffee0a ("ftrace: Add 'function-fork' trace option") Fixes: c37775d57830a ("tracing: Add infrastructure to allow set_event_pid to follow children" Signed-off-by: Steven Rostedt (VMware)

ftrace: Fix ftrace_trace_task return value

2020-08-03T20:12:31Z

I was attempting to use pid filtering with function_graph, but it wasn't allowing anything to make it through. Turns out ftrace_trace_task returns false if ftrace_ignore_pid is not-empty, which isn't correct anymore. We're now setting it to FTRACE_PID_IGNORE if we need to ignore that pid, otherwise it's set to the pid (which is weird considering the name) or to FTRACE_PID_TRACE. Fix the check to check for != FTRACE_PID_IGNORE. With this we can now use function_graph with pid filtering. Link: https://lkml.kernel.org/r/20200725005048.1790-1-josef@toxicpanda.com Fixes: 717e3f5ebc82 ("ftrace: Make function trace pid filtering a bit more exact") Signed-off-by: Josef Bacik Signed-off-by: Steven Rostedt (VMware)

ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines

2020-07-31T02:45:31Z

When inserting a module, we find all ftrace_ops referencing it on the ftrace_ops_list. But FTRACE_OPS_FL_DIRECT and FTRACE_OPS_FL_IPMODIFY flags are special, and should not be set automatically. So warn and skip ftrace_ops that have these two flags set and adding new code. Also check if only one ftrace_ops references the module, in which case we can use a trampoline as an optimization. Link: https://lkml.kernel.org/r/20200728180554.65203-2-zhouchengming@bytedance.com Signed-off-by: Chengming Zhou Signed-off-by: Muchun Song Signed-off-by: Steven Rostedt (VMware)

ftrace: Setup correct FTRACE_FL_REGS flags for module

2020-07-30T23:35:19Z

When module loaded and enabled, we will use __ftrace_replace_code for module if any ftrace_ops referenced it found. But we will get wrong ftrace_addr for module rec in ftrace_get_addr_new, because rec->flags has not been setup correctly. It can cause the callback function of a ftrace_ops has FTRACE_OPS_FL_SAVE_REGS to be called with pt_regs set to NULL. So setup correct FTRACE_FL_REGS flags for rec when we call referenced_filters to find ftrace_ops references it. Link: https://lkml.kernel.org/r/20200728180554.65203-1-zhouchengming@bytedance.com Cc: stable@vger.kernel.org Fixes: 8c4f3c3fa9681 ("ftrace: Check module functions being traced on reload") Signed-off-by: Chengming Zhou Signed-off-by: Muchun Song Signed-off-by: Steven Rostedt (VMware)

Merge branch 'perf/vlbr'

2020-07-02T13:51:48Z