linux-stable.git/kernel/trace, branch v5.6.13

tracing: Add a vmalloc_sync_mappings() for safe measure

2020-05-14T05:59:22+00:00

commit 11f5efc3ab66284f7aaacc926e9351d658e2577b upstream.

x86_64 lazily maps in the vmalloc pages, and the way this works with per_cpu
areas can be complex, to say the least. Mappings may happen at boot up, and
if nothing synchronizes the page tables, those page mappings may not be
synced till they are used. This causes issues for anything that might touch
one of those mappings in the path of the page fault handler. When one of
those unmapped mappings is touched in the page fault handler, it will cause
another page fault, which in turn will cause a page fault, and leave us in
a loop of page faults.

Commit 763802b53a42 ("x86/mm: split vmalloc_sync_all()") split
vmalloc_sync_all() into vmalloc_sync_unmappings() and
vmalloc_sync_mappings(), as on system exit, it did not need to do a full
sync on x86_64 (although it still needed to be done on x86_32). By chance,
the vmalloc_sync_all() would synchronize the page mappings done at boot up
and prevent the per cpu area from being a problem for tracing in the page
fault handler. But when that synchronization in the exit of a task became a
nop, it caused the problem to appear.

Link: https://lore.kernel.org/r/20200429054857.66e8e333@oasis.local.home

Cc: stable@vger.kernel.org
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Reported-by: "Tzvetomir Stoyanov (VMware)" 
Suggested-by: Joerg Roedel 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: Wait for preempt irq delay thread to finish

2020-05-14T05:59:21+00:00

commit d16a8c31077e75ecb9427fbfea59b74eed00f698 upstream.

Running on a slower machine, it is possible that the preempt delay kernel
thread may still be executing if the module was immediately removed after
added, and this can cause the kernel to crash as the kernel thread might be
executing after its code has been removed.

There's no reason that the caller of the code shouldn't just wait for the
delay thread to finish, as the thread can also be created by a trigger in
the sysfs code, which also has the same issues.

Link: http://lore.kernel.org/r/5EA2B0C8.2080706@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 793937236d1ee ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Reported-by: Xiao Yang 
Reviewed-by: Xiao Yang 
Reviewed-by: Joel Fernandes 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/kprobes: Reject new event if loc is NULL

2020-05-14T05:59:21+00:00

commit 5b4dcd2d201a395ad4054067bfae4a07554fbd65 upstream.

Reject the new event which has NULL location for kprobes.
For kprobes, user must specify at least the location.

Link: http://lkml.kernel.org/r/158779376597.6082.1411212055469099461.stgit@devnote2

Cc: Tom Zanussi 
Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/boottime: Fix kprobe event API usage

2020-05-14T05:59:21+00:00

commit da0f1f4167e3af69e1d8b32d6d65195ddd2bfb64 upstream.

Fix boottime kprobe events to use API correctly for
multiple events.

For example, when we set a multiprobe kprobe events in
bootconfig like below,

  ftrace.event.kprobes.myevent {
  	probes = "vfs_read $arg1 $arg2", "vfs_write $arg1 $arg2"
  }

This cause an error;

  trace_boot: Failed to add probe: p:kprobes/myevent (null)  vfs_read $arg1 $arg2  vfs_write $arg1 $arg2

This shows the 1st argument becomes NULL and multiprobes
are merged to 1 probe.

Link: http://lkml.kernel.org/r/158779375766.6082.201939936008972838.stgit@devnote2

Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: 29a154810546 ("tracing: Change trace_boot to use kprobe_event interface")
Reviewed-by: Tom Zanussi 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/kprobes: Fix a double initialization typo

2020-05-14T05:59:13+00:00

[ Upstream commit dcbd21c9fca5e954fd4e3d91884907eb6d47187e ]

Fix a typo that resulted in an unnecessary double
initialization to addr.

Link: http://lkml.kernel.org/r/158779374968.6082.2337484008464939919.stgit@devnote2

Cc: Tom Zanussi 
Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: c7411a1a126f ("tracing/kprobe: Check whether the non-suffixed symbol is notrace")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

ftrace: Fix memory leak caused by not freeing entry in unregister_ftrace_direct()

2020-05-10T08:32:49+00:00

[ Upstream commit 353da87921a5ec654e7e9024e083f099f1b33c97 ]

kmemleak reported the following:

unreferenced object 0xffff90d47127a920 (size 32):
  comm "modprobe", pid 1766, jiffies 4294792031 (age 162.568s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 22 01 00 00 00 00 ad de  ........".......
    00 78 12 a7 ff ff ff ff 00 00 b6 c0 ff ff ff ff  .x..............
  backtrace:
    [<00000000bb79e72e>] register_ftrace_direct+0xcb/0x3a0
    [<00000000295e4f79>] do_one_initcall+0x72/0x340
    [<00000000873ead18>] do_init_module+0x5a/0x220
    [<00000000974d9de5>] load_module+0x2235/0x2550
    [<0000000059c3d6ce>] __do_sys_finit_module+0xc0/0x120
    [<000000005a8611b4>] do_syscall_64+0x60/0x230
    [<00000000a0cdc49e>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

The entry used to save the direct descriptor needs to be freed
when unregistering.

Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

tracing: Fix memory leaks in trace_events_hist.c

2020-05-10T08:32:49+00:00

[ Upstream commit 9da73974eb9c965dd9989befb593b8c8da9e4bdc ]

kmemleak report 1:
    [<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
    [<05a2c9ed>] create_field_var+0xcf/0x180
    [<528a2d68>] action_create+0xe2/0xc80
    [<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
    [<28ea5d3d>] trigger_process_regex+0x7b/0xc0
    [<3138e86f>] event_trigger_write+0x4d/0xb0
    [] __vfs_write+0x30/0x200
    [<4f424a0d>] vfs_write+0x96/0x1b0
    [] ksys_write+0x53/0xc0
    [<3717101a>] __ia32_sys_write+0x15/0x20
    [] do_fast_syscall_32+0x70/0x250
    [<46e2629c>] entry_SYSENTER_32+0xaf/0x102

This is because save_vars[] of struct hist_trigger_data are
not destroyed

kmemleak report 2:
    [<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
    [<6e5e97c5>] create_var+0x3c/0x110
    [] create_field_var+0xaf/0x180
    [<528a2d68>] action_create+0xe2/0xc80
    [<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
    [<28ea5d3d>] trigger_process_regex+0x7b/0xc0
    [<3138e86f>] event_trigger_write+0x4d/0xb0
    [] __vfs_write+0x30/0x200
    [<4f424a0d>] vfs_write+0x96/0x1b0
    [] ksys_write+0x53/0xc0
    [<3717101a>] __ia32_sys_write+0x15/0x20
    [] do_fast_syscall_32+0x70/0x250
    [<46e2629c>] entry_SYSENTER_32+0xaf/0x102

struct hist_field allocated through create_var() do not initialize
"ref" field to 1. The code in __destroy_hist_field() does not destroy
object if "ref" is initialized to zero, the condition
if (--hist_field->ref > 1) always passes since unsigned int wraps.

kmemleak report 3:
    [] __kmalloc_track_caller+0x139/0x2b0
    [] kstrdup+0x27/0x50
    [<39d70006>] init_var_ref+0x58/0xd0
    [<8ca76370>] create_var_ref+0x89/0xe0
    [] action_create+0x38f/0xc80
    [<7c146821>] event_hist_trigger_func+0x15b5/0x1920
    [<07de3f61>] trigger_process_regex+0x7b/0xc0
    [] event_trigger_write+0x4d/0xb0
    [<19bf1512>] __vfs_write+0x30/0x200
    [<64ce4d27>] vfs_write+0x96/0x1b0
    [] ksys_write+0x53/0xc0
    [<7d4230cd>] __ia32_sys_write+0x15/0x20
    [<8eadca00>] do_fast_syscall_32+0x70/0x250
    [<235cf985>] entry_SYSENTER_32+0xaf/0x102

hist_fields (system & event_name) are not freed

Link: http://lkml.kernel.org/r/20200422061503.GA5151@cosmos

Signed-off-by: Vamshi K Sthambamkadi 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation

2020-04-21T07:08:09+00:00

commit 0bbe7f719985efd9adb3454679ecef0984cb6800 upstream.

Traced event can trigger 'snapshot' operation(i.e. calls snapshot_trigger()
or snapshot_count_trigger()) when register_snapshot_trigger() has completed
registration but doesn't allocate buffer for 'snapshot' event trigger.  In
the rare case, 'snapshot' operation always detects the lack of allocated
buffer so make register_snapshot_trigger() allocate buffer first.

trigger-snapshot.tc in kselftest reproduces the issue on slow vm:
-----------------------------------------------------------
cat trace
...
ftracetest-3028  [002] ....   236.784290: sched_process_fork: comm=ftracetest pid=3028 child_comm=ftracetest child_pid=3036
     <...>-2875  [003] ....   240.460335: tracing_snapshot_instance_cond: *** SNAPSHOT NOT ALLOCATED ***
     <...>-2875  [003] ....   240.460338: tracing_snapshot_instance_cond: *** stopping trace here!   ***
-----------------------------------------------------------

Link: http://lkml.kernel.org/r/20200414015145.66236-1-yangx.jy@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 93e31ffbf417a ("tracing: Add 'snapshot' event trigger command")
Signed-off-by: Xiao Yang 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace/kprobe: Show the maxactive number on kprobe_events

2020-04-17T14:13:45+00:00

commit 6a13a0d7b4d1171ef9b80ad69abc37e1daa941b3 upstream.

Show maxactive parameter on kprobe_events.
This allows user to save the current configuration and
restore it without losing maxactive parameter.

Link: http://lkml.kernel.org/r/4762764a-6df7-bc93-ed60-e336146dce1f@gmail.com
Link: http://lkml.kernel.org/r/158503528846.22706.5549974121212526020.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 696ced4fb1d76 ("tracing/kprobes: expose maxactive for kretprobe in kprobe_events")
Reported-by: Taeung Song 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2020-03-13T18:13:45+00:00

Alexei Starovoitov says:

====================
pull-request: bpf 2020-03-12

The following pull-request contains BPF updates for your *net* tree.

We've added 12 non-merge commits during the last 8 day(s) which contain
a total of 12 files changed, 161 insertions(+), 15 deletions(-).

The main changes are:

1) Andrii fixed two bugs in cgroup-bpf.

2) John fixed sockmap.

3) Luke fixed x32 jit.

4) Martin fixed two issues in struct_ops.

5) Yonghong fixed bpf_send_signal.

6) Yoshiki fixed BTF enum.
====================

Signed-off-by: David S. Miller