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 --- scripts/dev-needs.sh | 315 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 315 insertions(+) create mode 100755 scripts/dev-needs.sh (limited to 'scripts/dev-needs.sh') diff --git a/scripts/dev-needs.sh b/scripts/dev-needs.sh new file mode 100755 index 000000000..454cc304f --- /dev/null +++ b/scripts/dev-needs.sh @@ -0,0 +1,315 @@ +#! /bin/sh +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2020, Google LLC. All rights reserved. +# Author: Saravana Kannan + +function help() { + cat << EOF +Usage: $(basename $0) [-c|-d|-m|-f] [filter options] + +This script needs to be run on the target device once it has booted to a +shell. + +The script takes as input a list of one or more device directories under +/sys/devices and then lists the probe dependency chain (suppliers and +parents) of these devices. It does a breadth first search of the dependency +chain, so the last entry in the output is close to the root of the +dependency chain. + +By default it lists the full path to the devices under /sys/devices. + +It also takes an optional modifier flag as the first parameter to change +what information is listed in the output. If the requested information is +not available, the device name is printed. + + -c lists the compatible string of the dependencies + -d lists the driver name of the dependencies that have probed + -m lists the module name of the dependencies that have a module + -f list the firmware node path of the dependencies + -g list the dependencies as edges and nodes for graphviz + -t list the dependencies as edges for tsort + +The filter options provide a way to filter out some dependencies: + --allow-no-driver By default dependencies that don't have a driver + attached are ignored. This is to avoid following + device links to "class" devices that are created + when the consumer probes (as in, not a probe + dependency). If you want to follow these links + anyway, use this flag. + + --exclude-devlinks Don't follow device links when tracking probe + dependencies. + + --exclude-parents Don't follow parent devices when tracking probe + dependencies. + +EOF +} + +function dev_to_detail() { + local i=0 + while [ $i -lt ${#OUT_LIST[@]} ] + do + local C=${OUT_LIST[i]} + local S=${OUT_LIST[i+1]} + local D="'$(detail_chosen $C $S)'" + if [ ! -z "$D" ] + then + # This weirdness is needed to work with toybox when + # using the -t option. + printf '%05u\t%s\n' ${i} "$D" | tr -d \' + fi + i=$((i+2)) + done +} + +function already_seen() { + local i=0 + while [ $i -lt ${#OUT_LIST[@]} ] + do + if [ "$1" = "${OUT_LIST[$i]}" ] + then + # if-statement treats 0 (no-error) as true + return 0 + fi + i=$(($i+2)) + done + + # if-statement treats 1 (error) as false + return 1 +} + +# Return 0 (no-error/true) if parent was added +function add_parent() { + + if [ ${ALLOW_PARENTS} -eq 0 ] + then + return 1 + fi + + local CON=$1 + # $CON could be a symlink path. So, we need to find the real path and + # then go up one level to find the real parent. + local PARENT=$(realpath $CON/..) + + while [ ! -e ${PARENT}/driver ] + do + if [ "$PARENT" = "/sys/devices" ] + then + return 1 + fi + PARENT=$(realpath $PARENT/..) + done + + CONSUMERS+=($PARENT) + OUT_LIST+=(${CON} ${PARENT}) + return 0 +} + +# Return 0 (no-error/true) if one or more suppliers were added +function add_suppliers() { + local CON=$1 + local RET=1 + + if [ ${ALLOW_DEVLINKS} -eq 0 ] + then + return 1 + fi + + SUPPLIER_LINKS=$(ls -1d $CON/supplier:* 2>/dev/null) + for SL in $SUPPLIER_LINKS; + do + SYNC_STATE=$(cat $SL/sync_state_only) + + # sync_state_only links are proxy dependencies. + # They can also have cycles. So, don't follow them. + if [ "$SYNC_STATE" != '0' ] + then + continue + fi + + SUPPLIER=$(realpath $SL/supplier) + + if [ ! -e $SUPPLIER/driver -a ${ALLOW_NO_DRIVER} -eq 0 ] + then + continue + fi + + CONSUMERS+=($SUPPLIER) + OUT_LIST+=(${CON} ${SUPPLIER}) + RET=0 + done + + return $RET +} + +function detail_compat() { + f=$1/of_node/compatible + if [ -e $f ] + then + echo -n $(cat $f) + else + echo -n $1 + fi +} + +function detail_module() { + f=$1/driver/module + if [ -e $f ] + then + echo -n $(basename $(realpath $f)) + else + echo -n $1 + fi +} + +function detail_driver() { + f=$1/driver + if [ -e $f ] + then + echo -n $(basename $(realpath $f)) + else + echo -n $1 + fi +} + +function detail_fwnode() { + f=$1/firmware_node + if [ ! -e $f ] + then + f=$1/of_node + fi + + if [ -e $f ] + then + echo -n $(realpath $f) + else + echo -n $1 + fi +} + +function detail_graphviz() { + if [ "$2" != "ROOT" ] + then + echo -n "\"$(basename $2)\"->\"$(basename $1)\"" + else + echo -n "\"$(basename $1)\"" + fi +} + +function detail_tsort() { + echo -n "\"$2\" \"$1\"" +} + +function detail_device() { echo -n $1; } + +alias detail=detail_device +ALLOW_NO_DRIVER=0 +ALLOW_DEVLINKS=1 +ALLOW_PARENTS=1 + +while [ $# -gt 0 ] +do + ARG=$1 + case $ARG in + --help) + help + exit 0 + ;; + -c) + alias detail=detail_compat + ;; + -m) + alias detail=detail_module + ;; + -d) + alias detail=detail_driver + ;; + -f) + alias detail=detail_fwnode + ;; + -g) + alias detail=detail_graphviz + ;; + -t) + alias detail=detail_tsort + ;; + --allow-no-driver) + ALLOW_NO_DRIVER=1 + ;; + --exclude-devlinks) + ALLOW_DEVLINKS=0 + ;; + --exclude-parents) + ALLOW_PARENTS=0 + ;; + *) + # Stop at the first argument that's not an option. + break + ;; + esac + shift +done + +function detail_chosen() { + detail $1 $2 +} + +if [ $# -eq 0 ] +then + help + exit 1 +fi + +CONSUMERS=($@) +OUT_LIST=() + +# Do a breadth first, non-recursive tracking of suppliers. The parent is also +# considered a "supplier" as a device can't probe without its parent. +i=0 +while [ $i -lt ${#CONSUMERS[@]} ] +do + CONSUMER=$(realpath ${CONSUMERS[$i]}) + i=$(($i+1)) + + if already_seen ${CONSUMER} + then + continue + fi + + # If this is not a device with a driver, we don't care about its + # suppliers. + if [ ! -e ${CONSUMER}/driver -a ${ALLOW_NO_DRIVER} -eq 0 ] + then + continue + fi + + ROOT=1 + + # Add suppliers to CONSUMERS list and output the consumer details. + # + # We don't need to worry about a cycle in the dependency chain causing + # infinite loops. That's because the kernel doesn't allow cycles in + # device links unless it's a sync_state_only device link. And we ignore + # sync_state_only device links inside add_suppliers. + if add_suppliers ${CONSUMER} + then + ROOT=0 + fi + + if add_parent ${CONSUMER} + then + ROOT=0 + fi + + if [ $ROOT -eq 1 ] + then + OUT_LIST+=(${CONSUMER} "ROOT") + fi +done + +# Can NOT combine sort and uniq using sort -suk2 because stable sort in toybox +# isn't really stable. +dev_to_detail | sort -k2 -k1 | uniq -f 1 | sort | cut -f2- + +exit 0 -- cgit v1.3.1