kernel/linux.git/Documentation/trace, branch v6.1.168

Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram

2025-10-15T09:56:35+00:00

[ Upstream commit 8c716e87ea33519920811338100d6d8a7fb32456 ] Section heading for sched_waking histogram is shown as normal paragraph instead due to codeblock marker for the following diagram being in the same line as the section underline. Separate them. Fixes: daceabf1b494 ("tracing/doc: Fix ascii-art in histogram-design.rst") Reviewed-by: Tom Zanussi Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Bagas Sanjaya Acked-by: Steven Rostedt (Google) Signed-off-by: Jonathan Corbet Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com> Signed-off-by: Sasha Levin

tracing/probes: Add symstr type for dynamic events

2023-08-03T08:23:54+00:00

[ Upstream commit b26a124cbfa80f42bfc4e63e1d5643ca98159d66 ] Add 'symstr' type for storing the kernel symbol as a string data instead of the symbol address. This allows us to filter the events by wildcard symbol name. e.g. # echo 'e:wqfunc workqueue.workqueue_execute_start symname=$function:symstr' >> dynamic_events # cat events/eprobes/wqfunc/format name: wqfunc ID: 2110 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:__data_loc char[] symname; offset:8; size:4; signed:1; print fmt: " symname=\"%s\"", __get_str(symname) Note that there is already 'symbol' type which just change the print format (so it still stores the symbol address in the tracing ring buffer.) On the other hand, 'symstr' type stores the actual "symbol+offset/size" data as a string. Link: https://lore.kernel.org/all/166679930847.1528100.4124308529180235965.stgit@devnote3/ Signed-off-by: Masami Hiramatsu (Google) Stable-dep-of: 66bcf65d6cf0 ("tracing/probes: Fix to avoid double count of the string length on the array") Signed-off-by: Sasha Levin

attr: use consistent sgid stripping checks

2023-03-03T10:52:25+00:00

commit ed5a7047d2011cb6b2bf84ceb6680124cc6a7d95 upstream. Currently setgid stripping in file_remove_privs()'s should_remove_suid() helper is inconsistent with other parts of the vfs. Specifically, it only raises ATTR_KILL_SGID if the inode is S_ISGID and S_IXGRP but not if the inode isn't in the caller's groups and the caller isn't privileged over the inode although we require this already in setattr_prepare() and setattr_copy() and so all filesystem implement this requirement implicitly because they have to use setattr_{prepare,copy}() anyway. But the inconsistency shows up in setgid stripping bugs for overlayfs in xfstests (e.g., generic/673, generic/683, generic/685, generic/686, generic/687). For example, we test whether suid and setgid stripping works correctly when performing various write-like operations as an unprivileged user (fallocate, reflink, write, etc.): echo "Test 1 - qa_user, non-exec file $verb" setup_testfile chmod a+rws $junk_file commit_and_check "$qa_user" "$verb" 64k 64k The test basically creates a file with 6666 permissions. While the file has the S_ISUID and S_ISGID bits set it does not have the S_IXGRP set. On a regular filesystem like xfs what will happen is: sys_fallocate() -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> setattr_copy() In should_remove_suid() we can see that ATTR_KILL_SUID is raised unconditionally because the file in the test has S_ISUID set. But we also see that ATTR_KILL_SGID won't be set because while the file is S_ISGID it is not S_IXGRP (see above) which is a condition for ATTR_KILL_SGID being raised. So by the time we call notify_change() we have attr->ia_valid set to ATTR_KILL_SUID | ATTR_FORCE. Now notify_change() sees that ATTR_KILL_SUID is set and does: ia_valid = attr->ia_valid |= ATTR_MODE attr->ia_mode = (inode->i_mode & ~S_ISUID); which means that when we call setattr_copy() later we will definitely update inode->i_mode. Note that attr->ia_mode still contains S_ISGID. Now we call into the filesystem's ->setattr() inode operation which will end up calling setattr_copy(). Since ATTR_MODE is set we will hit: if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode); if (!vfsgid_in_group_p(vfsgid) && !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) mode &= ~S_ISGID; inode->i_mode = mode; } and since the caller in the test is neither capable nor in the group of the inode the S_ISGID bit is stripped. But assume the file isn't suid then ATTR_KILL_SUID won't be raised which has the consequence that neither the setgid nor the suid bits are stripped even though it should be stripped because the inode isn't in the caller's groups and the caller isn't privileged over the inode. If overlayfs is in the mix things become a bit more complicated and the bug shows up more clearly. When e.g., ovl_setattr() is hit from ovl_fallocate()'s call to file_remove_privs() then ATTR_KILL_SUID and ATTR_KILL_SGID might be raised but because the check in notify_change() is questioning the ATTR_KILL_SGID flag again by requiring S_IXGRP for it to be stripped the S_ISGID bit isn't removed even though it should be stripped: sys_fallocate() -> vfs_fallocate() -> ovl_fallocate() -> file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> ovl_setattr() // TAKE ON MOUNTER'S CREDS -> ovl_do_notify_change() -> notify_change() // GIVE UP MOUNTER'S CREDS // TAKE ON MOUNTER'S CREDS -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = attr_force | kill; -> notify_change() The fix for all of this is to make file_remove_privs()'s should_remove_suid() helper to perform the same checks as we already require in setattr_prepare() and setattr_copy() and have notify_change() not pointlessly requiring S_IXGRP again. It doesn't make any sense in the first place because the caller must calculate the flags via should_remove_suid() anyway which would raise ATTR_KILL_SGID. While we're at it we move should_remove_suid() from inode.c to attr.c where it belongs with the rest of the iattr helpers. Especially since it returns ATTR_KILL_S{G,U}ID flags. We also rename it to setattr_should_drop_suidgid() to better reflect that it indicates both setuid and setgid bit removal and also that it returns attr flags. Running xfstests with this doesn't report any regressions. We should really try and use consistent checks. Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner (Microsoft) Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman

kprobes: kretprobe events missing on 2-core KVM guest

2023-01-04T10:28:58+00:00

[ Upstream commit 3b7ddab8a19aefc768f345fd3782af35b4a68d9b ] Default value of maxactive is set as num_possible_cpus() for nonpreemptable systems. For a 2-core system, only 2 kretprobe instances would be allocated in default, then these 2 instances for execve kretprobe are very likely to be used up with a pipelined command. Here's the testcase: a shell script was added to crontab, and the content of the script is: #!/bin/sh do_something_magic `tr -dc a-z < /dev/urandom | head -c 10` cron will trigger a series of program executions (4 times every hour). Then events loss would be noticed normally after 3-4 hours of testings. The issue is caused by a burst of series of execve requests. The best number of kretprobe instances could be different case by case, and should be user's duty to determine, but num_possible_cpus() as the default value is inadequate especially for systems with small number of cpus. This patch enables the logic for preemption as default, thus increases the minimum of maxactive to 10 for nonpreemptable systems. Link: https://lore.kernel.org/all/20221110081502.492289-1-wuqiang.matt@bytedance.com/ Signed-off-by: wuqiang Reviewed-by: Solar Designer Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin

tracing/histogram: Update document for KEYS_MAX size

2022-10-18T21:41:56+00:00

After commit 4f36c2d85ced ("tracing: Increase tracing map KEYS_MAX size"), 'keys' supports up to three fields. Signed-off-by: Zheng Yejian Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20221017103806.2479139-1-zhengyejian1@huawei.com Signed-off-by: Jonathan Corbet

Merge tag 'docs-6.1-2' of git://git.lwn.net/linux

2022-10-13T17:58:32+00:00

Pull documentation fixes from Jonathan Corbet: "A handful of relatively simple documentation fixes, plus a set of patches catching the Chinese translation up with the front-page rework" * tag 'docs-6.1-2' of git://git.lwn.net/linux: Documentation: rtla: Correct command line example docs/zh_CN: add a man-pages link to zh_CN/index.rst docs/zh_CN: Rewrite the Chinese translation front page docs/zh_CN: add zh_CN/arch.rst docs/zh_CN: promote the title of zh_CN/process/index.rst docs/zh_CN: Update the translation of page_owner to 6.0-rc7 docs/zh_CN: Update the translation of ksm to 6.0-rc7 docs/howto: Replace abundoned URL of gmane.org Documentation: ubifs: Fix compression idiom Documentation/mm/page_owner.rst: delete frequently changing experimental data docs/zh_CN: Fix build warning docs: ftrace: Correct access mode

Merge tag 'perf-tools-for-v6.1-1-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

2022-10-11T22:02:25+00:00

Pull perf tools updates from Arnaldo Carvalho de Melo: - Add support for AMD on 'perf mem' and 'perf c2c', the kernel enablement patches went via tip. Example: $ sudo perf mem record -- -c 10000 ^C[ perf record: Woken up 227 times to write data ] [ perf record: Captured and wrote 58.760 MB perf.data (836978 samples) ] $ sudo perf mem report -F mem,sample,snoop Samples: 836K of event 'ibs_op//', Event count (approx.): 8418762 Memory access Samples Snoop N/A 700620 N/A L1 hit 126675 N/A L2 hit 424 N/A L3 hit 664 HitM L3 hit 10 N/A Local RAM hit 2 N/A Remote RAM (1 hop) hit 8558 N/A Remote Cache (1 hop) hit 3 N/A Remote Cache (1 hop) hit 2 HitM Remote Cache (2 hops) hit 10 HitM Remote Cache (2 hops) hit 6 N/A Uncached hit 4 N/A $ - "perf lock" improvements: - Add -E/--entries option to limit the number of entries to display, say to ask for just the top 5 contended locks. - Add -q/--quiet option to suppress header and debug messages. - Add a 'perf test' kernel lock contention entry to test 'perf lock'. - "perf lock contention" improvements: - Ask BPF's bpf_get_stackid() to skip some callchain entries. The ones closer to the tooling are bpf related and not that interesting, the ones calling the locking function are the ones we're interested in, example of a full, unskipped callstack: - Allow changing the callstack depth and number of entries to skip. 1 10.74 us 10.74 us 10.74 us spinlock __bpf_trace_contention_begin+0xb 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffbb8b8e75 bpf_trace_run2+0x35 0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb 0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5 0xffffffffbc1c26ff _raw_spin_lock+0x1f 0xffffffffbb841015 tick_do_update_jiffies64+0x25 0xffffffffbb8409ee tick_irq_enter+0x9e - Show full callstack in verbose mode (-v option), sometimes this is desirable instead of showing just one callstack entry. - Allow multiple time ranges in 'perf record --delay' to help in reducing the amount of data collected from hardware tracing (Intel PT, etc) when there is a rough idea of periods of time where events of interest take time. - Add Intel PT to record only decoder debug messages when error happens. - Improve layout of Intel PT man page. - Add new branch types: alignment, data and inst faults and arch specific ones, such as fiq, debug_halt, debug_exit, debug_inst and debug_data on arm64. Kernel enablement went thru the tip tree. - Fix 'perf probe' error log check in 'perf test' when no debuginfo is available. - Fix 'perf stat' aggregation mode logic, it should be looking at the CPU not at the core number. - Fix flags parsing in 'perf trace' filters. - Introduce compact encoding of CPU range encoding on perf.data, to avoid having a bitmap with all the CPUs. - Improvements to the 'perf stat' metrics, including adding "core_wide", and computing "smt" from the CPU topology. - Add support to the new PERF_FORMAT_LOST perf_event_attr.read_format, that allows tooling to ask for the precise number of lost samples for a given event. - Add 'addr' sort key to see just the address of sampled instructions: $ perf record -o- true | perf report -i- -s addr [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] # Samples: 12 of event 'cycles:u' # Event count (approx.): 252512 # # Overhead Address # ........ .................. 42.96% 0x7f96f08443d7 29.55% 0x7f96f0859b50 14.76% 0x7f96f0852e02 8.30% 0x7f96f0855028 4.43% 0xffffffff8de01087 perf annotate: Toggle full address <-> offset display - Add 'f' hotkey to the 'perf annotate' TUI interface when in 'disassembler output' mode ('o' hotkey) to toggle showing full virtual address or just the offset. - Cache DSO build-ids when synthesizing PERF_RECORD_MMAP records for pre-existing threads, at the start of a 'perf record' session, speeding up that record startup phase. - Add a command line option to specify build ids in 'perf inject'. - Update JSON event files for the Intel alderlake, broadwell, broadwellde, broadwellx, cascadelakex, haswell, haswellx, icelake, icelakex, ivybridge, ivytown, jaketown, sandybridge, sapphirerapids, skylake, skylakex, and tigerlake processors. - Update vendor JSON event files for the ARM Neoverse V1 and E1 platforms. - Add a 'perf test' entry for 'perf mem' where a struct has false sharing and this gets detected in the 'perf mem' output, tested with Intel, AMD and ARM64 systems. - Add a 'perf test' entry to test the resolution of java symbols, where an output like this is expected: 8.18% jshell jitted-50116-29.so [.] Interpreter 0.75% Thread-1 jitted-83602-1670.so [.] jdk.internal.jimage.BasicImageReader.getString(int) - Add tests for the ARM64 CoreSight hardware tracing feature, with specially crafted pureloop, memcpy, thread loop and unroll tread that then gets traced and the output compared with expected output. Documentation explaining it is also included. - Add per thread Intel PT 'perf test' entry to check that PERF_RECORD_TEXT_POKE events are recorded per CPU, resulting in a mixture of per thread and per CPU events and mmaps, verify that this gets all recorded correctly. - Introduce pthread mutex wrappers to allow for building with clang's -Wthread-safety, i.e. using the "guarded_by" "pt_guarded_by" "lockable", "exclusive_lock_function", "exclusive_trylock_function", "exclusive_locks_required", and "no_thread_safety_analysis" compiler function attributes. - Fix empty version number when building outside of a git repo. - Improve feature detection display when multiple versions of a feature are present, such as for binutils libbfd, that has a mix of possible ways to detect according to the Linux distribution. Previously in some cases we had: Auto-detecting system features ... libbfd: [ on ] ... libbfd-liberty: [ on ] ... libbfd-liberty-z: [ on ] Now for this case we show just the main feature: Auto-detecting system features ... libbfd: [ on ] - Remove some unused structs, variables, macros, function prototypes and includes from various places. * tag 'perf-tools-for-v6.1-1-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (169 commits) perf script: Add missing fields in usage hint perf mem: Print "LFB/MAB" for PERF_MEM_LVLNUM_LFB perf mem/c2c: Avoid printing empty lines for unsupported events perf mem/c2c: Add load store event mappings for AMD perf mem/c2c: Set PERF_SAMPLE_WEIGHT for LOAD_STORE events perf mem: Add support for printing PERF_MEM_LVLNUM_{CXL|IO} perf amd ibs: Sync arch/x86/include/asm/amd-ibs.h header with the kernel tools headers UAPI: Sync include/uapi/linux/perf_event.h header with the kernel perf stat: Fix cpu check to use id.cpu.cpu in aggr_printout() perf test coresight: Add relevant documentation about ARM64 CoreSight testing perf test: Add git ignore for tmp and output files of ARM CoreSight tests perf test coresight: Add unroll thread test shell script perf test coresight: Add unroll thread test tool perf test coresight: Add thread loop test shell scripts perf test coresight: Add thread loop test tool perf test coresight: Add memcpy thread test shell script perf test coresight: Add memcpy thread test tool perf test: Add git ignore for perf data generated by the ARM CoreSight tests perf test: Add arm64 asm pureloop test shell script perf test: Add asm pureloop test tool ...

Merge tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2022-10-10T19:20:55+00:00

Pull tracing updates from Steven Rostedt: "Major changes: - Changed location of tracing repo from personal git repo to: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git - Added Masami Hiramatsu as co-maintainer - Updated MAINTAINERS file to separate out FTRACE as it is more than just TRACING. Minor changes: - Added Mark Rutland as FTRACE reviewer - Updated user_events to make it on its way to remove the BROKEN tag. The changes should now be acceptable but will run it through a cycle and hopefully we can remove the BROKEN tag next release. - Added filtering to eprobes - Added a delta time to the benchmark trace event - Have the histogram and filter callbacks called via a switch statement instead of indirect functions. This speeds it up to avoid retpolines. - Add a way to wake up ring buffer waiters waiting for the ring buffer to fill up to its watermark. - New ioctl() on the trace_pipe_raw file to wake up ring buffer waiters. - Wake up waiters when the ring buffer is disabled. A reader may block when the ring buffer is disabled, but if it was blocked when the ring buffer is disabled it should then wake up. Fixes: - Allow splice to read partially read ring buffer pages. This fixes splice never moving forward. - Fix inverted compare that made the "shortest" ring buffer wait queue actually the longest. - Fix a race in the ring buffer between resetting a page when a writer goes to another page, and the reader. - Fix ftrace accounting bug when function hooks are added at boot up before the weak functions are set to "disabled". - Fix bug that freed a user allocated snapshot buffer when enabling a tracer. - Fix possible recursive locks in osnoise tracer - Fix recursive locking direct functions - Other minor clean ups and fixes" * tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (44 commits) ftrace: Create separate entry in MAINTAINERS for function hooks tracing: Update MAINTAINERS to reflect new tracing git repo tracing: Do not free snapshot if tracer is on cmdline ftrace: Still disable enabled records marked as disabled tracing/user_events: Move pages/locks into groups to prepare for namespaces tracing: Add Masami Hiramatsu as co-maintainer tracing: Remove unused variable 'dups' MAINTAINERS: add myself as a tracing reviewer ring-buffer: Fix race between reset page and reading page tracing/user_events: Update ABI documentation to align to bits vs bytes tracing/user_events: Use bits vs bytes for enabled status page data tracing/user_events: Use refcount instead of atomic for ref tracking tracing/user_events: Ensure user provided strings are safely formatted tracing/user_events: Use WRITE instead of READ for io vector import tracing/user_events: Use NULL for strstr checks tracing: Fix spelling mistake "preapre" -> "prepare" tracing: Wake up waiters when tracing is disabled tracing: Add ioctl() to force ring buffer waiters to wake up tracing: Wake up ring buffer waiters on closing of the file ring-buffer: Add ring_buffer_wake_waiters() ...

docs: ftrace: Correct access mode

2022-10-10T18:50:53+00:00

The documentation gives an example for opening trace marker with write-only mode, but the flag WR_ONLY is not defined by glibc. Use O_WRONLY to replace it. Signed-off-by: Leo Yan Acked-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20221008083250.3160-1-leo.yan@linaro.org Signed-off-by: Jonathan Corbet

Merge tag 'char-misc-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2022-10-08T15:56:37+00:00

Pull char/misc and other driver updates from Greg KH: "Here is the large set of char/misc and other small driver subsystem changes for 6.1-rc1. Loads of different things in here: - IIO driver updates, additions, and changes. Probably the largest part of the diffstat - habanalabs driver update with support for new hardware and features, the second largest part of the diff. - fpga subsystem driver updates and additions - mhi subsystem updates - Coresight driver updates - gnss subsystem updates - extcon driver updates - icc subsystem updates - fsi subsystem updates - nvmem subsystem and driver updates - misc driver updates - speakup driver additions for new features - lots of tiny driver updates and cleanups All of these have been in the linux-next tree for a while with no reported issues" * tag 'char-misc-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (411 commits) w1: Split memcpy() of struct cn_msg flexible array spmi: pmic-arb: increase SPMI transaction timeout delay spmi: pmic-arb: block access for invalid PMIC arbiter v5 SPMI writes spmi: pmic-arb: correct duplicate APID to PPID mapping logic spmi: pmic-arb: add support to dispatch interrupt based on IRQ status spmi: pmic-arb: check apid against limits before calling irq handler spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup_irq spmi: pmic-arb: handle spurious interrupt spmi: pmic-arb: add a print in cleanup_irq drivers: spmi: Directly use ida_alloc()/free() MAINTAINERS: add TI ECAP driver info counter: ti-ecap-capture: capture driver support for ECAP Documentation: ABI: sysfs-bus-counter: add frequency & num_overflows items dt-bindings: counter: add ti,am62-ecap-capture.yaml counter: Introduce the COUNTER_COMP_ARRAY component type counter: Consolidate Counter extension sysfs attribute creation counter: Introduce the Count capture component counter: 104-quad-8: Add Signal polarity component counter: Introduce the Signal polarity component counter: interrupt-cnt: Implement watch_validate callback ...