From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- Documentation/ABI/testing/sysfs-mce | 97 +++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-mce (limited to 'Documentation/ABI/testing/sysfs-mce') diff --git a/Documentation/ABI/testing/sysfs-mce b/Documentation/ABI/testing/sysfs-mce new file mode 100644 index 000000000..83172f50e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-mce @@ -0,0 +1,97 @@ +What: /sys/devices/system/machinecheck/machinecheckX/ +Contact: Andi Kleen +Date: Feb, 2007 +Description: + (X = CPU number) + + Machine checks report internal hardware error conditions + detected by the CPU. Uncorrected errors typically cause a + machine check (often with panic), corrected ones cause a + machine check log entry. + + For more details about the x86 machine check architecture + see the Intel and AMD architecture manuals from their + developer websites. + + For more details about the architecture + see http://one.firstfloor.org/~andi/mce.pdf + + Each CPU has its own directory. + +What: /sys/devices/system/machinecheck/machinecheckX/bank +Contact: Andi Kleen +Date: Feb, 2007 +Description: + (Y bank number) + + 64bit Hex bitmask enabling/disabling specific subevents for + bank Y. + + When a bit in the bitmask is zero then the respective + subevent will not be reported. + + By default all events are enabled. + + Note that BIOS maintain another mask to disable specific events + per bank. This is not visible here + +What: /sys/devices/system/machinecheck/machinecheckX/check_interval +Contact: Andi Kleen +Date: Feb, 2007 +Description: + The entries appear for each CPU, but they are truly shared + between all CPUs. + + How often to poll for corrected machine check errors, in + seconds (Note output is hexadecimal). Default 5 minutes. + When the poller finds MCEs it triggers an exponential speedup + (poll more often) on the polling interval. When the poller + stops finding MCEs, it triggers an exponential backoff + (poll less often) on the polling interval. The check_interval + variable is both the initial and maximum polling interval. + 0 means no polling for corrected machine check errors + (but some corrected errors might be still reported + in other ways) + +What: /sys/devices/system/machinecheck/machinecheckX/trigger +Contact: Andi Kleen +Date: Feb, 2007 +Description: + The entries appear for each CPU, but they are truly shared + between all CPUs. + + Program to run when a machine check event is detected. + This is an alternative to running mcelog regularly from cron + and allows to detect events faster. + +What: /sys/devices/system/machinecheck/machinecheckX/monarch_timeout +Contact: Andi Kleen +Date: Feb, 2007 +Description: + How long to wait for the other CPUs to machine check too on a + exception. 0 to disable waiting for other CPUs. + + Unit: us + +What: /sys/devices/system/machinecheck/machinecheckX/ignore_ce +Contact: Hidetoshi Seto +Date: Jun 2009 +Description: + Disables polling and CMCI for corrected errors. + All corrected events are not cleared and kept in bank MSRs. + +What: /sys/devices/system/machinecheck/machinecheckX/dont_log_ce +Contact: Hidetoshi Seto +Date: Jun 2009 +Description: + Disables logging for corrected errors. + All reported corrected errors will be cleared silently. + + This option will be useful if you never care about corrected + errors. + +What: /sys/devices/system/machinecheck/machinecheckX/cmci_disabled +Contact: Hidetoshi Seto +Date: Jun 2009 +Description: + Disables the CMCI feature. -- cgit v1.3.1