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/userspace-api/dcdbas.rst | 99 ++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 Documentation/userspace-api/dcdbas.rst (limited to 'Documentation/userspace-api/dcdbas.rst') diff --git a/Documentation/userspace-api/dcdbas.rst b/Documentation/userspace-api/dcdbas.rst new file mode 100644 index 000000000..309cc57a7 --- /dev/null +++ b/Documentation/userspace-api/dcdbas.rst @@ -0,0 +1,99 @@ +=================================== +Dell Systems Management Base Driver +=================================== + +Overview +======== + +The Dell Systems Management Base Driver provides a sysfs interface for +systems management software such as Dell OpenManage to perform system +management interrupts and host control actions (system power cycle or +power off after OS shutdown) on certain Dell systems. + +Dell OpenManage requires this driver on the following Dell PowerEdge systems: +300, 1300, 1400, 400SC, 500SC, 1500SC, 1550, 600SC, 1600SC, 650, 1655MC, +700, and 750. Other Dell software such as the open source libsmbios project +is expected to make use of this driver, and it may include the use of this +driver on other Dell systems. + +The Dell libsmbios project aims towards providing access to as much BIOS +information as possible. See http://linux.dell.com/libsmbios/main/ for +more information about the libsmbios project. + + +System Management Interrupt +=========================== + +On some Dell systems, systems management software must access certain +management information via a system management interrupt (SMI). The SMI data +buffer must reside in 32-bit address space, and the physical address of the +buffer is required for the SMI. The driver maintains the memory required for +the SMI and provides a way for the application to generate the SMI. +The driver creates the following sysfs entries for systems management +software to perform these system management interrupts:: + + /sys/devices/platform/dcdbas/smi_data + /sys/devices/platform/dcdbas/smi_data_buf_phys_addr + /sys/devices/platform/dcdbas/smi_data_buf_size + /sys/devices/platform/dcdbas/smi_request + +Systems management software must perform the following steps to execute +a SMI using this driver: + +1) Lock smi_data. +2) Write system management command to smi_data. +3) Write "1" to smi_request to generate a calling interface SMI or + "2" to generate a raw SMI. +4) Read system management command response from smi_data. +5) Unlock smi_data. + + +Host Control Action +=================== + +Dell OpenManage supports a host control feature that allows the administrator +to perform a power cycle or power off of the system after the OS has finished +shutting down. On some Dell systems, this host control feature requires that +a driver perform a SMI after the OS has finished shutting down. + +The driver creates the following sysfs entries for systems management software +to schedule the driver to perform a power cycle or power off host control +action after the system has finished shutting down: + +/sys/devices/platform/dcdbas/host_control_action +/sys/devices/platform/dcdbas/host_control_smi_type +/sys/devices/platform/dcdbas/host_control_on_shutdown + +Dell OpenManage performs the following steps to execute a power cycle or +power off host control action using this driver: + +1) Write host control action to be performed to host_control_action. +2) Write type of SMI that driver needs to perform to host_control_smi_type. +3) Write "1" to host_control_on_shutdown to enable host control action. +4) Initiate OS shutdown. + (Driver will perform host control SMI when it is notified that the OS + has finished shutting down.) + + +Host Control SMI Type +===================== + +The following table shows the value to write to host_control_smi_type to +perform a power cycle or power off host control action: + +=================== ===================== +PowerEdge System Host Control SMI Type +=================== ===================== + 300 HC_SMITYPE_TYPE1 + 1300 HC_SMITYPE_TYPE1 + 1400 HC_SMITYPE_TYPE2 + 500SC HC_SMITYPE_TYPE2 + 1500SC HC_SMITYPE_TYPE2 + 1550 HC_SMITYPE_TYPE2 + 600SC HC_SMITYPE_TYPE2 + 1600SC HC_SMITYPE_TYPE2 + 650 HC_SMITYPE_TYPE2 + 1655MC HC_SMITYPE_TYPE2 + 700 HC_SMITYPE_TYPE3 + 750 HC_SMITYPE_TYPE3 +=================== ===================== -- cgit v1.3.1