linux/kernel/events, branch v5.6

Merge tag 'perf-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-02-09T20:04:09Z

Pull perf fixes from Thomas Gleixner: "A set of fixes and improvements for the perf subsystem: Kernel fixes: - Install cgroup events to the correct CPU context to prevent a potential list double add - Prevent an integer underflow in the perf mlock accounting - Add a missing prototype for arch_perf_update_userpage() Tooling: - Add a missing unlock in the error path of maps__insert() in perf maps. - Fix the build with the latest libbfd - Fix the perf parser so it does not delete parse event terms, which caused a regression for using perf with the ARM CoreSight as the sink configuration was missing due to the deletion. - Fix the double free in the perf CPU map merging test case - Add the missing ustring support for the perf probe command" * tag 'perf-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf maps: Add missing unlock to maps__insert() error case perf probe: Add ustring support for perf probe command perf: Make perf able to build with latest libbfd perf test: Fix test case Merge cpu map perf parse: Copy string to perf_evsel_config_term perf parse: Refactor 'struct perf_evsel_config_term' kernel/events: Add a missing prototype for arch_perf_update_userpage() perf/cgroups: Install cgroup events to correct cpuctx perf/core: Fix mlock accounting in perf_mmap()

Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-02-06T07:12:11Z

Pull tracing updates from Steven Rostedt: - Added new "bootconfig". This looks for a file appended to initrd to add boot config options, and has been discussed thoroughly at Linux Plumbers. Very useful for adding kprobes at bootup. Only enabled if "bootconfig" is on the real kernel command line. - Created dynamic event creation. Merges common code between creating synthetic events and kprobe events. - Rename perf "ring_buffer" structure to "perf_buffer" - Rename ftrace "ring_buffer" structure to "trace_buffer" Had to rename existing "trace_buffer" to "array_buffer" - Allow trace_printk() to work withing (some) tracing code. - Sort of tracing configs to be a little better organized - Fixed bug where ftrace_graph hash was not being protected properly - Various other small fixes and clean ups * tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits) bootconfig: Show the number of nodes on boot message tools/bootconfig: Show the number of bootconfig nodes bootconfig: Add more parse error messages bootconfig: Use bootconfig instead of boot config ftrace: Protect ftrace_graph_hash with ftrace_sync ftrace: Add comment to why rcu_dereference_sched() is open coded tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu tracing: Annotate ftrace_graph_hash pointer with __rcu bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline tracing: Use seq_buf for building dynevent_cmd string tracing: Remove useless code in dynevent_arg_pair_add() tracing: Remove check_arg() callbacks from dynevent args tracing: Consolidate some synth_event_trace code tracing: Fix now invalid var_ref_vals assumption in trace action tracing: Change trace_boot to use synth_event interface tracing: Move tracing selftests to bottom of menu tracing: Move mmio tracer config up with the other tracers tracing: Move tracing test module configs together tracing: Move all function tracing configs together tracing: Documentation for in-kernel synthetic event API ...

Merge branch 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-01-29T19:20:24Z

Pull openat2 support from Al Viro: "This is the openat2() series from Aleksa Sarai. I'm afraid that the rest of namei stuff will have to wait - it got zero review the last time I'd posted #work.namei, and there had been a leak in the posted series I'd caught only last weekend. I was going to repost it on Monday, but the window opened and the odds of getting any review during that... Oh, well. Anyway, openat2 part should be ready; that _did_ get sane amount of review and public testing, so here it comes" From Aleksa's description of the series: "For a very long time, extending openat(2) with new features has been incredibly frustrating. This stems from the fact that openat(2) is possibly the most famous counter-example to the mantra "don't silently accept garbage from userspace" -- it doesn't check whether unknown flags are present[1]. This means that (generally) the addition of new flags to openat(2) has been fraught with backwards-compatibility issues (O_TMPFILE has to be defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old kernels gave errors, since it's insecure to silently ignore the flag[2]). All new security-related flags therefore have a tough road to being added to openat(2). Furthermore, the need for some sort of control over VFS's path resolution (to avoid malicious paths resulting in inadvertent breakouts) has been a very long-standing desire of many userspace applications. This patchset is a revival of Al Viro's old AT_NO_JUMPS[3] patchset (which was a variant of David Drysdale's O_BENEATH patchset[4] which was a spin-off of the Capsicum project[5]) with a few additions and changes made based on the previous discussion within [6] as well as others I felt were useful. In line with the conclusions of the original discussion of AT_NO_JUMPS, the flag has been split up into separate flags. However, instead of being an openat(2) flag it is provided through a new syscall openat2(2) which provides several other improvements to the openat(2) interface (see the patch description for more details). The following new LOOKUP_* flags are added: LOOKUP_NO_XDEV: Blocks all mountpoint crossings (upwards, downwards, or through absolute links). Absolute pathnames alone in openat(2) do not trigger this. Magic-link traversal which implies a vfsmount jump is also blocked (though magic-link jumps on the same vfsmount are permitted). LOOKUP_NO_MAGICLINKS: Blocks resolution through /proc/$pid/fd-style links. This is done by blocking the usage of nd_jump_link() during resolution in a filesystem. The term "magic-links" is used to match with the only reference to these links in Documentation/, but I'm happy to change the name. It should be noted that this is different to the scope of ~LOOKUP_FOLLOW in that it applies to all path components. However, you can do openat2(NO_FOLLOW|NO_MAGICLINKS) on a magic-link and it will *not* fail (assuming that no parent component was a magic-link), and you will have an fd for the magic-link. In order to correctly detect magic-links, the introduction of a new LOOKUP_MAGICLINK_JUMPED state flag was required. LOOKUP_BENEATH: Disallows escapes to outside the starting dirfd's tree, using techniques such as ".." or absolute links. Absolute paths in openat(2) are also disallowed. Conceptually this flag is to ensure you "stay below" a certain point in the filesystem tree -- but this requires some additional to protect against various races that would allow escape using "..". Currently LOOKUP_BENEATH implies LOOKUP_NO_MAGICLINKS, because it can trivially beam you around the filesystem (breaking the protection). In future, there might be similar safety checks done as in LOOKUP_IN_ROOT, but that requires more discussion. In addition, two new flags are added that expand on the above ideas: LOOKUP_NO_SYMLINKS: Does what it says on the tin. No symlink resolution is allowed at all, including magic-links. Just as with LOOKUP_NO_MAGICLINKS this can still be used with NOFOLLOW to open an fd for the symlink as long as no parent path had a symlink component. LOOKUP_IN_ROOT: This is an extension of LOOKUP_BENEATH that, rather than blocking attempts to move past the root, forces all such movements to be scoped to the starting point. This provides chroot(2)-like protection but without the cost of a chroot(2) for each filesystem operation, as well as being safe against race attacks that chroot(2) is not. If a race is detected (as with LOOKUP_BENEATH) then an error is generated, and similar to LOOKUP_BENEATH it is not permitted to cross magic-links with LOOKUP_IN_ROOT. The primary need for this is from container runtimes, which currently need to do symlink scoping in userspace[7] when opening paths in a potentially malicious container. There is a long list of CVEs that could have bene mitigated by having RESOLVE_THIS_ROOT (such as CVE-2017-1002101, CVE-2017-1002102, CVE-2018-15664, and CVE-2019-5736, just to name a few). In order to make all of the above more usable, I'm working on libpathrs[8] which is a C-friendly library for safe path resolution. It features a userspace-emulated backend if the kernel doesn't support openat2(2). Hopefully we can get userspace to switch to using it, and thus get openat2(2) support for free once it's ready. Future work would include implementing things like RESOLVE_NO_AUTOMOUNT and possibly a RESOLVE_NO_REMOTE (to allow programs to be sure they don't hit DoSes though stale NFS handles)" * 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Documentation: path-lookup: include new LOOKUP flags selftests: add openat2(2) selftests open: introduce openat2(2) syscall namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution namei: LOOKUP_IN_ROOT: chroot-like scoped resolution namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution namei: LOOKUP_NO_XDEV: block mountpoint crossing namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution namei: LOOKUP_NO_SYMLINKS: block symlink resolution namei: allow set_root() to produce errors namei: allow nd_jump_link() to produce errors nsfs: clean-up ns_get_path() signature to return int namei: only return -ECHILD from follow_dotdot_rcu()

perf/cgroups: Install cgroup events to correct cpuctx

2020-01-28T20:20:19Z

cgroup events are always installed in the cpuctx. However, when it is not installed via IPI, list_update_cgroup_event() adds it to cpuctx of current CPU, which triggers list corruption: [] list_add double add: new=ffff888ff7cf0db0, prev=ffff888ff7ce82f0, next=ffff888ff7cf0db0. To reproduce this, we can simply run: # perf stat -e cs -a & # perf stat -e cs -G anycgroup Fix this by installing it to cpuctx that contains event->ctx, and the proper cgrp_cpuctx_list. Fixes: db0503e4f675 ("perf/core: Optimize perf_install_in_event()") Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Link: https://lkml.kernel.org/r/20200122195027.2112449-1-songliubraving@fb.com

perf/core: Fix mlock accounting in perf_mmap()

2020-01-28T20:20:18Z

Decreasing sysctl_perf_event_mlock between two consecutive perf_mmap()s of a perf ring buffer may lead to an integer underflow in locked memory accounting. This may lead to the undesired behaviors, such as failures in BPF map creation. Address this by adjusting the accounting logic to take into account the possibility that the amount of already locked memory may exceed the current limit. Fixes: c4b75479741c ("perf/core: Make the mlock accounting simple again") Suggested-by: Alexander Shishkin Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Acked-by: Alexander Shishkin Link: https://lkml.kernel.org/r/20200123181146.2238074-1-songliubraving@fb.com

perf: Correctly handle failed perf_get_aux_event()

2020-01-17T10:32:44Z

Vince reports a worrying issue: | so I was tracking down some odd behavior in the perf_fuzzer which turns | out to be because perf_even_open() sometimes returns 0 (indicating a file | descriptor of 0) even though as far as I can tell stdin is still open. ... and further the cause: | error is triggered if aux_sample_size has non-zero value. | | seems to be this line in kernel/events/core.c: | | if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) | goto err_locked; | | (note, err is never set) This seems to be a thinko in commit: ab43762ef010967e ("perf: Allow normal events to output AUX data") ... and we should probably return -EINVAL here, as this should only happen when the new event is mis-configured or does not have a compatible aux_event group leader. Fixes: ab43762ef010967e ("perf: Allow normal events to output AUX data") Reported-by: Vince Weaver Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Alexander Shishkin Tested-by: Vince Weaver

perf: Make struct ring_buffer less ambiguous

2020-01-13T18:19:38Z

eBPF requires needing to know the size of the perf ring buffer structure. But it unfortunately has the same name as the generic ring buffer used by tracing and oprofile. To make it less ambiguous, rename the perf ring buffer structure to "perf_buffer". As other parts of the ring buffer code has "perf_" as the prefix, it only makes sense to give the ring buffer the "perf_" prefix as well. Link: https://lore.kernel.org/r/20191213153553.GE20583@krava Acked-by: Peter Zijlstra Suggested-by: Alexei Starovoitov Signed-off-by: Steven Rostedt (VMware)

perf/core: Add SRCU annotation for pmus list walk

2019-12-17T12:32:46Z

Since commit 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking") there is an additional check to ensure that a RCU related lock is held while the RCU list is iterated. This section holds the SRCU reader lock instead. Add annotation to list_for_each_entry_rcu() that pmus_srcu must be acquired during the list traversal. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Joel Fernandes (Google) Link: https://lkml.kernel.org/r/20191119121429.zhcubzdhm672zasg@linutronix.de

nsfs: clean-up ns_get_path() signature to return int

2019-12-09T00:09:37Z

ns_get_path() and ns_get_path_cb() only ever return either NULL or an ERR_PTR. It is far more idiomatic to simply return an integer, and it makes all of the callers of ns_get_path() more straightforward to read. Fixes: e149ed2b805f ("take the targets of /proc/*/ns/* symlinks to separate fs") Signed-off-by: Aleksa Sarai Signed-off-by: Al Viro

mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area

2019-12-01T14:29:19Z

get_unmapped_area() returns an address or -errno on failure. Historically we have checked for the failure by offset_in_page() which is correct but quite hard to read. Newer code started using IS_ERR_VALUE which is much easier to read. Convert remaining users of offset_in_page as well. [mhocko@suse.com: rewrite changelog] [mhocko@kernel.org: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com Signed-off-by: Gaowei Pu Reviewed-by: Andrew Morton Acked-by: Michal Hocko Cc: Vlastimil Babka Cc: Wei Yang Cc: Konstantin Khlebnikov Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Cc: Mike Kravetz Cc: Rik van Riel Cc: Qian Cai Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds