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 --- fs/proc/Kconfig | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 fs/proc/Kconfig (limited to 'fs/proc/Kconfig') diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig new file mode 100644 index 000000000..24f5a36f4 --- /dev/null +++ b/fs/proc/Kconfig @@ -0,0 +1,128 @@ +# SPDX-License-Identifier: GPL-2.0-only +config PROC_FS + bool "/proc file system support" if EXPERT + default y + help + This is a virtual file system providing information about the status + of the system. "Virtual" means that it doesn't take up any space on + your hard disk: the files are created on the fly by the kernel when + you try to access them. Also, you cannot read the files with older + version of the program less: you need to use more or cat. + + It's totally cool; for example, "cat /proc/interrupts" gives + information about what the different IRQs are used for at the moment + (there is a small number of Interrupt ReQuest lines in your computer + that are used by the attached devices to gain the CPU's attention -- + often a source of trouble if two devices are mistakenly configured + to use the same IRQ). The program procinfo to display some + information about your system gathered from the /proc file system. + + Before you can use the /proc file system, it has to be mounted, + meaning it has to be given a location in the directory hierarchy. + That location should be /proc. A command such as "mount -t proc proc + /proc" or the equivalent line in /etc/fstab does the job. + + The /proc file system is explained in the file + and on the proc(5) manpage + ("man 5 proc"). + + This option will enlarge your kernel by about 67 KB. Several + programs depend on this, so everyone should say Y here. + +config PROC_KCORE + bool "/proc/kcore support" if !ARM + depends on PROC_FS && MMU + select VMCORE_INFO + help + Provides a virtual ELF core file of the live kernel. This can + be read with gdb and other ELF tools. No modifications can be + made using this mechanism. + +config PROC_VMCORE + bool "/proc/vmcore support" + depends on PROC_FS && CRASH_DUMP + default y + help + Exports the dump image of crashed kernel in ELF format. + +config PROC_VMCORE_DEVICE_DUMP + bool "Device Hardware/Firmware Log Collection" + depends on PROC_VMCORE + default n + help + After kernel panic, device drivers can collect the device + specific snapshot of their hardware or firmware before the + underlying devices are initialized in crash recovery kernel. + Note that the device driver must be present in the crash + recovery kernel's initramfs to collect its underlying device + snapshot. + + If you say Y here, the collected device dumps will be added + as ELF notes to /proc/vmcore. You can still disable device + dump using the kernel command line option 'novmcoredd'. + +config NEED_PROC_VMCORE_DEVICE_RAM + bool + +config PROC_VMCORE_DEVICE_RAM + def_bool y + depends on PROC_VMCORE && NEED_PROC_VMCORE_DEVICE_RAM + depends on VIRTIO_MEM + help + If the elfcore hdr is allocated and prepared by the dump kernel + ("2nd kernel") instead of the crashed kernel, RAM provided by memory + devices such as virtio-mem will not be included in the dump + image, because only the device driver can properly detect them. + + With this config enabled, these RAM ranges will be queried from the + device drivers once the device gets probed, so they can be included + in the crash dump. + + Relevant architectures should select NEED_PROC_VMCORE_DEVICE_RAM. + +config SYSCTL + bool "Sysctl support (/proc/sys)" if EXPERT + depends on PROC_FS + default y + help + The sysctl interface provides a means of dynamically changing + certain kernel parameters and variables on the fly without requiring + a recompile of the kernel or reboot of the system. The primary + interface is through /proc/sys. If you say Y here a tree of + modifiable sysctl entries will be generated beneath the + /proc/sys directory. They are explained in the files + in . Note that enabling this + option will enlarge the kernel by at least 8 KB. + + As it is generally a good thing, you should say Y here unless + building a kernel for install/rescue disks or your system is very + limited in memory. + +config PROC_PAGE_MONITOR + default y + depends on PROC_FS && MMU + bool "Enable /proc page monitoring" if EXPERT + help + Various /proc files exist to monitor process memory utilization: + /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, + /proc/kpagecount, and /proc/kpageflags. Disabling these + interfaces will reduce the size of the kernel by approximately 4kb. + +config PROC_CHILDREN + bool "Include /proc//task//children file" + depends on PROC_FS + default n + help + Provides a fast way to retrieve first level children pids of a task. See + for more information. + + Say Y if you are running any user-space software which takes benefit from + this interface. For example, rkt is such a piece of software. + +config PROC_PID_ARCH_STATUS + def_bool n + depends on PROC_FS + +config PROC_CPU_RESCTRL + def_bool n + depends on PROC_FS -- cgit v1.3.1