linux/kernel/trace/trace_event_perf.c, branch v5.8

Merge branch 'perf/urgent' into perf/core, to pick up fixes

2019-10-28T11:38:26Z

Signed-off-by: Ingo Molnar

tracing: Fix race in perf_trace_buf initialization

2019-10-21T23:38:28Z

A race condition exists while initialiazing perf_trace_buf from perf_trace_init() and perf_kprobe_init(). CPU0 CPU1 perf_trace_init() mutex_lock(&event_mutex) perf_trace_event_init() perf_trace_event_reg() total_ref_count == 0 buf = alloc_percpu() perf_trace_buf[i] = buf tp_event->class->reg() //fails perf_kprobe_init() goto fail perf_trace_event_init() perf_trace_event_reg() fail: total_ref_count == 0 total_ref_count == 0 buf = alloc_percpu() perf_trace_buf[i] = buf tp_event->class->reg() total_ref_count++ free_percpu(perf_trace_buf[i]) perf_trace_buf[i] = NULL Any subsequent call to perf_trace_event_reg() will observe total_ref_count > 0, causing the perf_trace_buf to be always NULL. This can result in perf_trace_buf getting accessed from perf_trace_buf_alloc() without being initialized. Acquiring event_mutex in perf_kprobe_init() before calling perf_trace_event_init() should fix this race. The race caused the following bug: Unable to handle kernel paging request at virtual address 0000003106f2003c Mem abort info: ESR = 0x96000045 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000045 CM = 0, WnR = 1 user pgtable: 4k pages, 39-bit VAs, pgdp = ffffffc034b9b000 [0000003106f2003c] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000045 [#1] PREEMPT SMP Process syz-executor (pid: 18393, stack limit = 0xffffffc093190000) pstate: 80400005 (Nzcv daif +PAN -UAO) pc : __memset+0x20/0x1ac lr : memset+0x3c/0x50 sp : ffffffc09319fc50 __memset+0x20/0x1ac perf_trace_buf_alloc+0x140/0x1a0 perf_trace_sys_enter+0x158/0x310 syscall_trace_enter+0x348/0x7c0 el0_svc_common+0x11c/0x368 el0_svc_handler+0x12c/0x198 el0_svc+0x8/0xc Ramdumps showed the following: total_ref_count = 3 perf_trace_buf = ( 0x0 -> NULL, 0x0 -> NULL, 0x0 -> NULL, 0x0 -> NULL) Link: http://lkml.kernel.org/r/1571120245-4186-1-git-send-email-prsood@codeaurora.org Cc: stable@vger.kernel.org Fixes: e12f03d7031a9 ("perf/core: Implement the 'perf_kprobe' PMU") Acked-by: Song Liu Signed-off-by: Prateek Sood Signed-off-by: Steven Rostedt (VMware)

perf_event: Add support for LSM and SELinux checks

2019-10-17T19:31:55Z

In current mainline, the degree of access to perf_event_open(2) system call depends on the perf_event_paranoid sysctl. This has a number of limitations: 1. The sysctl is only a single value. Many types of accesses are controlled based on the single value thus making the control very limited and coarse grained. 2. The sysctl is global, so if the sysctl is changed, then that means all processes get access to perf_event_open(2) opening the door to security issues. This patch adds LSM and SELinux access checking which will be used in Android to access perf_event_open(2) for the purposes of attaching BPF programs to tracepoints, perf profiling and other operations from userspace. These operations are intended for production systems. 5 new LSM hooks are added: 1. perf_event_open: This controls access during the perf_event_open(2) syscall itself. The hook is called from all the places that the perf_event_paranoid sysctl is checked to keep it consistent with the systctl. The hook gets passed a 'type' argument which controls CPU, kernel and tracepoint accesses (in this context, CPU, kernel and tracepoint have the same semantics as the perf_event_paranoid sysctl). Additionally, I added an 'open' type which is similar to perf_event_paranoid sysctl == 3 patch carried in Android and several other distros but was rejected in mainline [1] in 2016. 2. perf_event_alloc: This allocates a new security object for the event which stores the current SID within the event. It will be useful when the perf event's FD is passed through IPC to another process which may try to read the FD. Appropriate security checks will limit access. 3. perf_event_free: Called when the event is closed. 4. perf_event_read: Called from the read(2) and mmap(2) syscalls for the event. 5. perf_event_write: Called from the ioctl(2) syscalls for the event. [1] https://lwn.net/Articles/696240/ Since Peter had suggest LSM hooks in 2016 [1], I am adding his Suggested-by tag below. To use this patch, we set the perf_event_paranoid sysctl to -1 and then apply selinux checking as appropriate (default deny everything, and then add policy rules to give access to domains that need it). In the future we can remove the perf_event_paranoid sysctl altogether. Suggested-by: Peter Zijlstra Co-developed-by: Peter Zijlstra Signed-off-by: Joel Fernandes (Google) Signed-off-by: Peter Zijlstra (Intel) Acked-by: James Morris Cc: Arnaldo Carvalho de Melo Cc: rostedt@goodmis.org Cc: Yonghong Song Cc: Kees Cook Cc: Ingo Molnar Cc: Alexei Starovoitov Cc: jeffv@google.com Cc: Jiri Olsa Cc: Daniel Borkmann Cc: primiano@google.com Cc: Song Liu Cc: rsavitski@google.com Cc: Namhyung Kim Cc: Matthew Garrett Link: https://lkml.kernel.org/r/20191014170308.70668-1-joel@joelfernandes.org

tracing: Pass type into tracing_generic_entry_update()

2019-07-16T19:14:48Z

All callers of tracing_generic_entry_update() have to initialize entry->type, so let's just simply move it inside. Link: http://lkml.kernel.org/r/20190525165802.25944-2-xiyou.wangcong@gmail.com Cc: Ingo Molnar Signed-off-by: Cong Wang Signed-off-by: Steven Rostedt (VMware)

tracing/perf: Use strndup_user() instead of buggy open-coded version

2019-02-21T15:35:10Z

The first version of this method was missing the check for `ret == PATH_MAX`; then such a check was added, but it didn't call kfree() on error, so there was still a small memory leak in the error case. Fix it by using strndup_user() instead of open-coding it. Link: http://lkml.kernel.org/r/20190220165443.152385-1-jannh@google.com Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 0eadcc7a7bc0 ("perf/core: Fix perf_uprobe_init()") Reviewed-by: Masami Hiramatsu Acked-by: Song Liu Signed-off-by: Jann Horn Signed-off-by: Steven Rostedt (VMware)

trace_uprobe: support reference counter in fd-based uprobe

2018-10-11T02:14:17Z

This patch enables uprobes with reference counter in fd-based uprobe. Highest 32 bits of perf_event_attr.config is used to stored offset of the reference count (semaphore). Format information in /sys/bus/event_source/devices/uprobe/format/ is updated to reflect this new feature. Link: http://lkml.kernel.org/r/20181002053636.1896903-1-songliubraving@fb.com Cc: Oleg Nesterov Acked-by: Peter Zijlstra (Intel) Reviewed-and-tested-by: Ravi Bangoria Signed-off-by: Song Liu Signed-off-by: Steven Rostedt (VMware)

tracing: Add SPDX License format tags to tracing files

2018-08-16T23:08:06Z

Add the SPDX License header to ease license compliance management. Signed-off-by: Steven Rostedt (VMware)

perf/core: Fix perf_uprobe_init()

2018-04-10T05:33:10Z

Similarly to the uprobe PMU fix in perf_kprobe_init(), fix error handling in perf_uprobe_init() as well. Reported-by: 范龙飞 Signed-off-by: Song Liu Acked-by: Masami Hiramatsu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: e12f03d7031a ("perf/core: Implement the 'perf_kprobe' PMU") Signed-off-by: Ingo Molnar

perf/core: Fix perf_kprobe_init()

2018-04-10T05:33:10Z

Fix error handling in perf_kprobe_init(): ================================================================== BUG: KASAN: slab-out-of-bounds in strlen+0x8e/0xa0 lib/string.c:482 Read of size 1 at addr ffff88003f9cc5c0 by task syz-executor2/23095 CPU: 0 PID: 23095 Comm: syz-executor2 Not tainted 4.16.0+ #24 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 print_address_description+0x6e/0x2c0 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x256/0x380 mm/kasan/report.c:412 strlen+0x8e/0xa0 lib/string.c:482 kstrdup+0x21/0x70 mm/util.c:55 alloc_trace_kprobe+0xc8/0x930 kernel/trace/trace_kprobe.c:325 create_local_trace_kprobe+0x4f/0x3a0 kernel/trace/trace_kprobe.c:1438 perf_kprobe_init+0x149/0x1f0 kernel/trace/trace_event_perf.c:264 perf_kprobe_event_init+0xa8/0x120 kernel/events/core.c:8407 perf_try_init_event+0xcb/0x2a0 kernel/events/core.c:9719 perf_init_event kernel/events/core.c:9750 [inline] perf_event_alloc+0x1367/0x1e20 kernel/events/core.c:10022 SYSC_perf_event_open+0x242/0x2330 kernel/events/core.c:10477 do_syscall_64+0x198/0x640 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Reported-by: 范龙飞 Signed-off-by: Masami Hiramatsu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Song Liu Cc: Thomas Gleixner Fixes: e12f03d7031a ("perf/core: Implement the 'perf_kprobe' PMU") Signed-off-by: Ingo Molnar

perf/core: Implement the 'perf_uprobe' PMU

2018-02-06T10:29:28Z

This patch adds perf_uprobe support with similar pattern as previous patch (for kprobe). Two functions, create_local_trace_uprobe() and destroy_local_trace_uprobe(), are created so a uprobe can be created and attached to the file descriptor created by perf_event_open(). Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Yonghong Song Reviewed-by: Josef Bacik Cc: Cc: Cc: Cc: Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20171206224518.3598254-7-songliubraving@fb.com Signed-off-by: Ingo Molnar