linux-stable.git/kernel/trace, branch v6.3.2

tracing/user_events: Ensure write index cannot be negative

2023-05-11T14:17:29+00:00

[ Upstream commit cd98c93286a30cc4588dfd02453bec63c2f4acf4 ]

The write index indicates which event the data is for and accesses a
per-file array. The index is passed by user processes during write()
calls as the first 4 bytes. Ensure that it cannot be negative by
returning -EINVAL to prevent out of bounds accesses.

Update ftrace self-test to ensure this occurs properly.

Link: https://lkml.kernel.org/r/20230425225107.8525-2-beaub@linux.microsoft.com

Fixes: 7f5a08c79df3 ("user_events: Add minimal support for trace_event into ftrace")
Reported-by: Doug Cook 
Signed-off-by: Beau Belgrave 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Sasha Levin

tracing: Fix permissions for the buffer_percent file

2023-05-11T14:16:52+00:00

commit 4f94559f40ad06d627c0fdfc3319cec778a2845b upstream.

This file defines both read and write operations, yet it is being
created as read-only. This means that it can't be written to without the
CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
to it without the need to override DAC perms.

Link: https://lore.kernel.org/linux-trace-kernel/20230503140114.3280002-1-omosnace@redhat.com

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu 
Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage")
Signed-off-by: Ondrej Mosnacek 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Greg Kroah-Hartman

ring-buffer: Sync IRQ works before buffer destruction

2023-05-11T14:16:50+00:00

commit 675751bb20634f981498c7d66161584080cc061e upstream.

If something was written to the buffer just before destruction,
it may be possible (maybe not in a real system, but it did
happen in ARCH=um with time-travel) to destroy the ringbuffer
before the IRQ work ran, leading this KASAN report (or a crash
without KASAN):

    BUG: KASAN: slab-use-after-free in irq_work_run_list+0x11a/0x13a
    Read of size 8 at addr 000000006d640a48 by task swapper/0

    CPU: 0 PID: 0 Comm: swapper Tainted: G        W  O       6.3.0-rc1 #7
    Stack:
     60c4f20f 0c203d48 41b58ab3 60f224fc
     600477fa 60f35687 60c4f20f 601273dd
     00000008 6101eb00 6101eab0 615be548
    Call Trace:
     [<60047a58>] show_stack+0x25e/0x282
     [<60c609e0>] dump_stack_lvl+0x96/0xfd
     [<60c50d4c>] print_report+0x1a7/0x5a8
     [<603078d3>] kasan_report+0xc1/0xe9
     [<60308950>] __asan_report_load8_noabort+0x1b/0x1d
     [<60232844>] irq_work_run_list+0x11a/0x13a
     [<602328b4>] irq_work_tick+0x24/0x34
     [<6017f9dc>] update_process_times+0x162/0x196
     [<6019f335>] tick_sched_handle+0x1a4/0x1c3
     [<6019fd9e>] tick_sched_timer+0x79/0x10c
     [<601812b9>] __hrtimer_run_queues.constprop.0+0x425/0x695
     [<60182913>] hrtimer_interrupt+0x16c/0x2c4
     [<600486a3>] um_timer+0x164/0x183
     [...]

    Allocated by task 411:
     save_stack_trace+0x99/0xb5
     stack_trace_save+0x81/0x9b
     kasan_save_stack+0x2d/0x54
     kasan_set_track+0x34/0x3e
     kasan_save_alloc_info+0x25/0x28
     ____kasan_kmalloc+0x8b/0x97
     __kasan_kmalloc+0x10/0x12
     __kmalloc+0xb2/0xe8
     load_elf_phdrs+0xee/0x182
     [...]

    The buggy address belongs to the object at 000000006d640800
     which belongs to the cache kmalloc-1k of size 1024
    The buggy address is located 584 bytes inside of
     freed 1024-byte region [000000006d640800, 000000006d640c00)

Add the appropriate irq_work_sync() so the work finishes before
the buffers are destroyed.

Prior to the commit in the Fixes tag below, there was only a
single global IRQ work, so this issue didn't exist.

Link: https://lore.kernel.org/linux-trace-kernel/20230427175920.a76159263122.I8295e405c44362a86c995e9c2c37e3e03810aa56@changeid

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu 
Fixes: 15693458c4bc ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: Johannes Berg 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Greg Kroah-Hartman

ring-buffer: Ensure proper resetting of atomic variables in ring_buffer_reset_online_cpus

2023-05-11T14:16:50+00:00

commit 7c339fb4d8577792378136c15fde773cfb863cb8 upstream.

In ring_buffer_reset_online_cpus, the buffer_size_kb write operation
may permanently fail if the cpu_online_mask changes between two
for_each_online_buffer_cpu loops. The number of increases and decreases
on both cpu_buffer->resize_disabled and cpu_buffer->record_disabled may be
inconsistent, causing some CPUs to have non-zero values for these atomic
variables after the function returns.

This issue can be reproduced by "echo 0 > trace" while hotplugging cpu.
After reproducing success, we can find out buffer_size_kb will not be
functional anymore.

To prevent leaving 'resize_disabled' and 'record_disabled' non-zero after
ring_buffer_reset_online_cpus returns, we ensure that each atomic variable
has been set up before atomic_sub() to it.

Link: https://lore.kernel.org/linux-trace-kernel/20230426062027.17451-1-Tze-nan.Wu@mediatek.com

Cc: stable@vger.kernel.org
Cc: 
Cc: npiggin@gmail.com
Fixes: b23d7a5f4a07 ("ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU")
Reviewed-by: Cheng-Jui Wang 
Signed-off-by: Tze-nan Wu 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Greg Kroah-Hartman

tracing/synthetic: Make lastcmd_mutex static

2023-04-06T19:08:18+00:00

The lastcmd_mutex is only used in trace_events_synth.c and should be
static.

Link: https://lore.kernel.org/linux-trace-kernel/202304062033.cRStgOuP-lkp@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230406111033.6e26de93@gandalf.local.home

Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Tze-nan Wu 
Fixes: 4ccf11c4e8a8e ("tracing/synthetic: Fix races on freeing last_cmd")
Reviewed-by: Mukesh Ojha 
Reported-by: kernel test robot 
Signed-off-by: Steven Rostedt (Google)

ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()

2023-04-06T15:01:30+00:00

Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct().

Root cause is 'direct->addr' was changed from 'old_addr' to 'new_addr' but
not restored if error happened on calling ftrace_modify_direct_caller().
Then it can no longer find 'direct' by that 'old_addr'.

To fix it, restore 'direct->addr' to 'old_addr' explicitly in error path.

Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Cc: 
Cc: 
Cc: 
Cc: 
Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.")
Signed-off-by: Zheng Yejian 
Signed-off-by: Steven Rostedt (Google)

tracing: Free error logs of tracing instances

2023-04-05T13:54:37+00:00

When a tracing instance is removed, the error messages that hold errors
that occurred in the instance needs to be freed. The following reports a
memory leak:

 # cd /sys/kernel/tracing
 # mkdir instances/foo
 # echo 'hist:keys=x' > instances/foo/events/sched/sched_switch/trigger
 # cat instances/foo/error_log
 [  117.404795] hist:sched:sched_switch: error: Couldn't find field
   Command: hist:keys=x
                      ^
 # rmdir instances/foo

Then check for memory leaks:

 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88810d8ec700 (size 192):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    60 dd 68 61 81 88 ff ff 60 dd 68 61 81 88 ff ff  `.ha....`.ha....
    a0 30 8c 83 ff ff ff ff 26 00 0a 00 00 00 00 00  .0......&.......
  backtrace:
    [<00000000dae26536>] kmalloc_trace+0x2a/0xa0
    [<00000000b2938940>] tracing_log_err+0x277/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc
unreferenced object 0xffff888170c35a00 (size 32):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    0a 20 20 43 6f 6d 6d 61 6e 64 3a 20 68 69 73 74  .  Command: hist
    3a 6b 65 79 73 3d 78 0a 00 00 00 00 00 00 00 00  :keys=x.........
  backtrace:
    [<000000006a747de5>] __kmalloc+0x4d/0x160
    [<000000000039df5f>] tracing_log_err+0x29b/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc

The problem is that the error log needs to be freed when the instance is
removed.

Link: https://lore.kernel.org/lkml/76134d9f-a5ba-6a0d-37b3-28310b4a1e91@alu.unizg.hr/
Link: https://lore.kernel.org/linux-trace-kernel/20230404194504.5790b95f@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu 
Cc: Andrew Morton 
Cc: Mark Rutland 
Cc: Thorsten Leemhuis 
Cc: Ulf Hansson 
Cc: Eric Biggers 
Fixes: 2f754e771b1a6 ("tracing: Have the error logs show up in the proper instances")
Reported-by: Mirsad Goran Todorovac 
Tested-by: Mirsad Todorovac 
Signed-off-by: Steven Rostedt (Google)

tracing: Fix ftrace_boot_snapshot command line logic

2023-04-05T02:29:53+00:00

The kernel command line ftrace_boot_snapshot by itself is supposed to
trigger a snapshot at the end of boot up of the main top level trace
buffer. A ftrace_boot_snapshot=foo will do the same for an instance called
foo that was created by trace_instance=foo,...

The logic was broken where if ftrace_boot_snapshot was by itself, it would
trigger a snapshot for all instances that had tracing enabled, regardless
if it asked for a snapshot or not.

When a snapshot is requested for a buffer, the buffer's
tr->allocated_snapshot is set to true. Use that to know if a trace buffer
wants a snapshot at boot up or not.

Since the top level buffer is part of the ftrace_trace_arrays list,
there's no reason to treat it differently than the other buffers. Just
iterate the list if ftrace_boot_snapshot was specified.

Link: https://lkml.kernel.org/r/20230405022341.895334039@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Andrew Morton 
Cc: Ross Zwisler 
Fixes: 9c1c251d670bc ("tracing: Allow boot instances to have snapshot buffers")
Signed-off-by: Steven Rostedt (Google)

tracing: Have tracing_snapshot_instance_cond() write errors to the appropriate instance

2023-04-05T02:29:53+00:00

If a trace instance has a failure with its snapshot code, the error
message is to be written to that instance's buffer. But currently, the
message is written to the top level buffer. Worse yet, it may also disable
the top level buffer and not the instance that had the issue.

Link: https://lkml.kernel.org/r/20230405022341.688730321@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Andrew Morton 
Cc: Ross Zwisler 
Fixes: 2824f50332486 ("tracing: Make the snapshot trigger work with instances")
Signed-off-by: Steven Rostedt (Google)

tracing/osnoise: Fix notify new tracing_max_latency

2023-04-03T15:52:46+00:00

osnoise/timerlat tracers are reporting new max latency on instances
where the tracing is off, creating inconsistencies between the max
reported values in the trace and in the tracing_max_latency. Thus
only report new tracing_max_latency on active tracing instances.

Link: https://lkml.kernel.org/r/ecd109fde4a0c24ab0f00ba1e9a144ac19a91322.1680104184.git.bristot@kernel.org

Cc: stable@vger.kernel.org
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Signed-off-by: Daniel Bristot de Oliveira 
Signed-off-by: Steven Rostedt (Google)