linux-stable.git/kernel/trace, branch v5.4.49

tracing/probe: Fix memleak in fetch_op_data operations

2020-06-24T15:50:51+00:00

commit 3aa8fdc37d16735e8891035becf25b3857d3efe0 upstream.

kmemleak report:
    [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0
    [] kstrndup+0x37/0x80
    [] parse_probe_arg.isra.7+0x3cc/0x630
    [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810
    [<655a7766>] trace_kprobe_create+0x2ca/0x950
    [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30
    [<6d1c8a52>] trace_run_command+0x67/0x80
    [] trace_parse_run_command+0xa7/0x140
    [] probes_write+0x10/0x20
    [<2027641c>] __vfs_write+0x30/0x1e0
    [<6a4aeee1>] vfs_write+0x96/0x1b0
    [<3517fb7d>] ksys_write+0x53/0xc0
    [] __ia32_sys_write+0x15/0x20
    [] do_syscall_32_irqs_on+0x3d/0x260
    [] do_fast_syscall_32+0x39/0xb0
    [] entry_SYSENTER_32+0xaf/0x102

Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
to FETCH_OP_ST_STRING, as a result memory is never freed since
traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types

Setup fetch string operation correctly after fetch_op_data operation.

Link: https://lkml.kernel.org/r/20200615143034.GA1734@cosmos

Cc: stable@vger.kernel.org
Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Acked-by: Masami Hiramatsu 
Signed-off-by: Vamshi K Sthambamkadi 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/probe: Fix bpf_task_fd_query() for kprobes and uprobes

2020-06-24T15:50:43+00:00

[ Upstream commit 22d5bd6867364b41576a712755271a7d6161abd6 ]

Commit 60d53e2c3b75 ("tracing/probe: Split trace_event related data from
trace_probe") removed the trace_[ku]probe structure from the
trace_event_call->data pointer. As bpf_get_[ku]probe_info() were
forgotten in that change, fix them now. These functions are currently
only used by the bpf_task_fd_query() syscall handler to collect
information about a perf event.

Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
Signed-off-by: Jean-Philippe Brucker 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Acked-by: Masami Hiramatsu 
Link: https://lore.kernel.org/bpf/20200608124531.819838-1-jean-philippe@linaro.org
Signed-off-by: Sasha Levin

blktrace: fix endianness for blk_log_remap()

2020-06-24T15:50:39+00:00

[ Upstream commit 5aec598c456fe3c1b71a1202cbb42bdc2a643277 ]

The function blk_log_remap() can be simplified by removing the
call to get_pdu_remap() that copies the values into extra variable to
print the data, which also fixes the endiannness warning reported by
sparse.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blktrace: fix endianness in get_pdu_int()

2020-06-24T15:50:39+00:00

[ Upstream commit 71df3fd82e7cccec7b749a8607a4662d9f7febdd ]

In function get_pdu_len() replace variable type from __u64 to
__be64. This fixes sparse warning.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blktrace: use errno instead of bi_status

2020-06-24T15:50:39+00:00

[ Upstream commit 48bc3cd3e07a1486f45d9971c75d6090976c3b1b ]

In blk_add_trace_spliti() blk_add_trace_bio_remap() use
blk_status_to_errno() to pass the error instead of pasing the bi_status.
This fixes the sparse warning.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

Stop the ad-hoc games with -Wno-maybe-initialized

2020-05-20T06:20:28+00:00

commit 78a5255ffb6a1af189a83e493d916ba1c54d8c75 upstream.

We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tracing: Add a vmalloc_sync_mappings() for safe measure

2020-05-14T05:58:25+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/kprobes: Fix a double initialization typo

2020-05-14T05:58:18+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

tracing: Fix memory leaks in trace_events_hist.c

2020-05-10T08:31:28+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

2020-04-21T07:04:59+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