linux/kernel/trace, branch v6.12

Merge tag 'trace-ringbuffer-v6.12-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2024-11-16T16:12:43Z

Pull ring buffer fixes from Steven Rostedt: - Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug" A crash that happened on cpu hotplug was actually caused by the incorrect ref counting that was fixed by commit 2cf9733891a4 ("ring-buffer: Fix refcount setting of boot mapped buffers"). The removal of calling cpu hotplug callbacks on memory mapped buffers was not an issue even though the tests at the time pointed toward it. But in fact, there's a check in that code that tests to see if the buffers are already allocated or not, and will not allocate them again if they are. Not calling the cpu hotplug callbacks ended up not initializing the non boot CPU buffers. Simply remove that change. - Clear all CPU buffers when starting tracing in a boot mapped buffer To properly process events from a previous boot, the address space needs to be accounted for due to KASLR and the events in the buffer are updated accordingly when read. This also requires that when the buffer has tracing enabled again in the current boot that the buffers are reset so that events from the previous boot do not interact with the events of the current boot and cause confusing due to not having the proper meta data. It was found that if a CPU is taken offline, that its per CPU buffer is not reset when tracing starts. This allows for events to be from both the previous boot and the current boot to be in the buffer at the same time. Clear all CPU buffers when tracing is started in a boot mapped buffer. * tag 'trace-ringbuffer-v6.12-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/ring-buffer: Clear all memory mapped CPU ring buffers on first recording Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug"

tracing/ring-buffer: Clear all memory mapped CPU ring buffers on first recording

2024-11-14T16:54:34Z

The events of a memory mapped ring buffer from the previous boot should not be mixed in with events from the current boot. There's meta data that is used to handle KASLR so that function names can be shown properly. Also, since the timestamps of the previous boot have no meaning to the timestamps of the current boot, having them intermingled in a buffer can also cause confusion because there could possibly be events in the future. When a trace is activated the meta data is reset so that the pointers of are now processed for the new address space. The trace buffers are reset when tracing starts for the first time. The problem here is that the reset only happens on online CPUs. If a CPU is offline, it does not get reset. To demonstrate the issue, a previous boot had tracing enabled in the boot mapped ring buffer on reboot. On the following boot, tracing has not been started yet so the function trace from the previous boot is still visible. # trace-cmd show -B boot_mapped -c 3 | tail -0 [003] d.h2. 156.462395: __rcu_read_lock <-cpu_emergency_disable_virtualization -0 [003] d.h2. 156.462396: vmx_emergency_disable_virtualization_cpu <-cpu_emergency_disable_virtualization -0 [003] d.h2. 156.462396: __rcu_read_unlock <-__sysvec_reboot -0 [003] d.h2. 156.462397: stop_this_cpu <-__sysvec_reboot -0 [003] d.h2. 156.462397: set_cpu_online <-stop_this_cpu -0 [003] d.h2. 156.462397: disable_local_APIC <-stop_this_cpu -0 [003] d.h2. 156.462398: clear_local_APIC <-disable_local_APIC -0 [003] d.h2. 156.462574: mcheck_cpu_clear <-stop_this_cpu -0 [003] d.h2. 156.462575: mce_intel_feature_clear <-stop_this_cpu -0 [003] d.h2. 156.462575: lmce_supported <-mce_intel_feature_clear Now, if CPU 3 is taken offline, and tracing is started on the memory mapped ring buffer, the events from the previous boot in the CPU 3 ring buffer is not reset. Now those events are using the meta data from the current boot and produces just hex values. # echo 0 > /sys/devices/system/cpu/cpu3/online # trace-cmd start -B boot_mapped -p function # trace-cmd show -B boot_mapped -c 3 | tail -0 [003] d.h2. 156.462395: 0xffffffff9a1e3194 <-0xffffffff9a0f655e -0 [003] d.h2. 156.462396: 0xffffffff9a0a1d24 <-0xffffffff9a0f656f -0 [003] d.h2. 156.462396: 0xffffffff9a1e6bc4 <-0xffffffff9a0f7323 -0 [003] d.h2. 156.462397: 0xffffffff9a0d12b4 <-0xffffffff9a0f732a -0 [003] d.h2. 156.462397: 0xffffffff9a1458d4 <-0xffffffff9a0d12e2 -0 [003] d.h2. 156.462397: 0xffffffff9a0faed4 <-0xffffffff9a0d12e7 -0 [003] d.h2. 156.462398: 0xffffffff9a0faaf4 <-0xffffffff9a0faef2 -0 [003] d.h2. 156.462574: 0xffffffff9a0e3444 <-0xffffffff9a0d12ef -0 [003] d.h2. 156.462575: 0xffffffff9a0e4964 <-0xffffffff9a0d12ef -0 [003] d.h2. 156.462575: 0xffffffff9a0e3fb0 <-0xffffffff9a0e496f Reset all CPUs when starting a boot mapped ring buffer for the first time, and not just the online CPUs. Fixes: 7a1d1e4b9639f ("tracing/ring-buffer: Add last_boot_info file to boot instance") Signed-off-by: Steven Rostedt (Google)

Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug"

2024-11-14T15:01:00Z

A crash happened when testing cpu hotplug with respect to the memory mapped ring buffers. It was assumed that the hot plug code was adding a per CPU buffer that was already created that caused the crash. The real problem was due to ref counting and was fixed by commit 2cf9733891a4 ("ring-buffer: Fix refcount setting of boot mapped buffers"). When a per CPU buffer is created, it will not be created again even with CPU hotplug, so the fix to not use CPU hotplug was a red herring. In fact, it caused only the boot CPU buffer to be created, leaving the other CPU per CPU buffers disabled. Revert that change as it was not the culprit of the fix it was intended to be. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20241113230839.6c03640f@gandalf.local.home Fixes: 912da2c384d5 ("ring-buffer: Do not have boot mapped buffers hook to CPU hotplug") Signed-off-by: Steven Rostedt (Google)

tracing: Document tracefs gid mount option

2024-11-01T12:57:17Z

Commit ee7f3666995d ("tracefs: Have new files inherit the ownership of their parent") and commit 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") introduced a new gid mount option that allows specifying a group to apply to all entries in tracefs. Document this in the tracing readme. Cc: Eric Sandeen Cc: Mathieu Desnoyers Cc: Shuah Khan Cc: Ali Zahraee Cc: Christian Brauner Cc: David Howells Cc: Masami Hiramatsu Link: https://lore.kernel.org/20241030171928.4168869-3-kaleshsingh@google.com Signed-off-by: Kalesh Singh Signed-off-by: Steven Rostedt (Google)

Merge tag 'ftrace-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2024-10-27T18:56:22Z

Pull ftrace fixes from Steven Rostedt: - Fix missing mutex unlock in error path of register_ftrace_graph() A previous fix added a return on an error path and forgot to unlock the mutex. Instead of dealing with error paths, use guard(mutex) as the mutex is just released at the exit of the function anyway. Other functions in this file should be updated with this, but that's a cleanup and not a fix. - Change cpuhp setup name to be consistent with other cpuhp states The same fix that the above patch fixes added a cpuhp_setup_state() call with the name of "fgraph_idle_init". I was informed that it should instead be something like: "fgraph:online". Update that too. * tag 'ftrace-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: fgraph: Change the name of cpuhp state to "fgraph:online" fgraph: Fix missing unlock in register_ftrace_graph()

fgraph: Change the name of cpuhp state to "fgraph:online"

2024-10-25T03:41:14Z

The cpuhp state name given to cpuhp_setup_state() is "fgraph_idle_init" which doesn't really conform to the names that are used for cpu hotplug setups. Instead rename it to "fgraph:online" to be in line with other states. Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Thomas Gleixner Link: https://lore.kernel.org/20241024222944.473d88c5@rorschach.local.home Suggested-by: Masami Hiramatsu Fixes: 2c02f7375e658 ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks") Signed-off-by: Steven Rostedt (Google)

fgraph: Fix missing unlock in register_ftrace_graph()

2024-10-25T02:26:06Z

Use guard(mutex)() to acquire and automatically release ftrace_lock, fixing the issue of not unlocking when calling cpuhp_setup_state() fails. Fixes smatch warning: kernel/trace/fgraph.c:1317 register_ftrace_graph() warn: inconsistent returns '&ftrace_lock'. Link: https://lore.kernel.org/20241024155917.1019580-1-lihuafei1@huawei.com Fixes: 2c02f7375e65 ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks") Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202410220121.wxg0olfd-lkp@intel.com/ Suggested-by: Steven Rostedt Signed-off-by: Li Huafei Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2024-10-24T23:53:20Z

Pull bpf fixes from Daniel Borkmann: - Fix an out-of-bounds read in bpf_link_show_fdinfo for BPF sockmap link file descriptors (Hou Tao) - Fix BPF arm64 JIT's address emission with tag-based KASAN enabled reserving not enough size (Peter Collingbourne) - Fix BPF verifier do_misc_fixups patching for inlining of the bpf_get_branch_snapshot BPF helper (Andrii Nakryiko) - Fix a BPF verifier bug and reject BPF program write attempts into read-only marked BPF maps (Daniel Borkmann) - Fix perf_event_detach_bpf_prog error handling by removing an invalid check which would skip BPF program release (Jiri Olsa) - Fix memory leak when parsing mount options for the BPF filesystem (Hou Tao) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf: Check validity of link->type in bpf_link_show_fdinfo() bpf: Add the missing BPF_LINK_TYPE invocation for sockmap bpf: fix do_misc_fixups() for bpf_get_branch_snapshot() bpf,perf: Fix perf_event_detach_bpf_prog error handling selftests/bpf: Add test for passing in uninit mtu_len selftests/bpf: Add test for writes to .rodata bpf: Remove MEM_UNINIT from skb/xdp MTU helpers bpf: Fix overloading of MEM_UNINIT's meaning bpf: Add MEM_WRITE attribute bpf: Preserve param->string when parsing mount options bpf, arm64: Fix address emission with tag-based KASAN enabled

bpf,perf: Fix perf_event_detach_bpf_prog error handling

2024-10-23T21:33:02Z

Peter reported that perf_event_detach_bpf_prog might skip to release the bpf program for -ENOENT error from bpf_prog_array_copy. This can't happen because bpf program is stored in perf event and is detached and released only when perf event is freed. Let's drop the -ENOENT check and make sure the bpf program is released in any case. Fixes: 170a7e3ea070 ("bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not found") Reported-by: Peter Zijlstra Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20241023200352.3488610-1-jolsa@kernel.org Closes: https://lore.kernel.org/lkml/20241022111638.GC16066@noisy.programming.kicks-ass.net/

tracing: Consider the NULL character when validating the event length

2024-10-23T08:24:47Z

strlen() returns a string length excluding the null byte. If the string length equals to the maximum buffer length, the buffer will have no space for the NULL terminating character. This commit checks this condition and returns failure for it. Link: https://lore.kernel.org/all/20241007144724.920954-1-leo.yan@arm.com/ Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") Signed-off-by: Leo Yan Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google)