No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Mohamed Khalfella 4815359056 tracing/histograms: Add histograms to hist_vars if they have referenced variables
commit 6018b585e8c6fa7d85d4b38d9ce49a5b67be7078 upstream.

Hist triggers can have referenced variables without having direct
variables fields. This can be the case if referenced variables are added
for trigger actions. In this case the newly added references will not
have field variables. Not taking such referenced variables into
consideration can result in a bug where it would be possible to remove
hist trigger with variables being refenced. This will result in a bug
that is easily reproducable like so

$ cd /sys/kernel/tracing
$ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events
$ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger
$ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger
$ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger

[  100.263533] ==================================================================
[  100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180
[  100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439
[  100.266320]
[  100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4
[  100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014
[  100.268561] Call Trace:
[  100.268902]  <TASK>
[  100.269189]  dump_stack_lvl+0x4c/0x70
[  100.269680]  print_report+0xc5/0x600
[  100.270165]  ? resolve_var_refs+0xc7/0x180
[  100.270697]  ? kasan_complete_mode_report_info+0x80/0x1f0
[  100.271389]  ? resolve_var_refs+0xc7/0x180
[  100.271913]  kasan_report+0xbd/0x100
[  100.272380]  ? resolve_var_refs+0xc7/0x180
[  100.272920]  __asan_load8+0x71/0xa0
[  100.273377]  resolve_var_refs+0xc7/0x180
[  100.273888]  event_hist_trigger+0x749/0x860
[  100.274505]  ? kasan_save_stack+0x2a/0x50
[  100.275024]  ? kasan_set_track+0x29/0x40
[  100.275536]  ? __pfx_event_hist_trigger+0x10/0x10
[  100.276138]  ? ksys_write+0xd1/0x170
[  100.276607]  ? do_syscall_64+0x3c/0x90
[  100.277099]  ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[  100.277771]  ? destroy_hist_data+0x446/0x470
[  100.278324]  ? event_hist_trigger_parse+0xa6c/0x3860
[  100.278962]  ? __pfx_event_hist_trigger_parse+0x10/0x10
[  100.279627]  ? __kasan_check_write+0x18/0x20
[  100.280177]  ? mutex_unlock+0x85/0xd0
[  100.280660]  ? __pfx_mutex_unlock+0x10/0x10
[  100.281200]  ? kfree+0x7b/0x120
[  100.281619]  ? ____kasan_slab_free+0x15d/0x1d0
[  100.282197]  ? event_trigger_write+0xac/0x100
[  100.282764]  ? __kasan_slab_free+0x16/0x20
[  100.283293]  ? __kmem_cache_free+0x153/0x2f0
[  100.283844]  ? sched_mm_cid_remote_clear+0xb1/0x250
[  100.284550]  ? __pfx_sched_mm_cid_remote_clear+0x10/0x10
[  100.285221]  ? event_trigger_write+0xbc/0x100
[  100.285781]  ? __kasan_check_read+0x15/0x20
[  100.286321]  ? __bitmap_weight+0x66/0xa0
[  100.286833]  ? _find_next_bit+0x46/0xe0
[  100.287334]  ? task_mm_cid_work+0x37f/0x450
[  100.287872]  event_triggers_call+0x84/0x150
[  100.288408]  trace_event_buffer_commit+0x339/0x430
[  100.289073]  ? ring_buffer_event_data+0x3f/0x60
[  100.292189]  trace_event_raw_event_sys_enter+0x8b/0xe0
[  100.295434]  syscall_trace_enter.constprop.0+0x18f/0x1b0
[  100.298653]  syscall_enter_from_user_mode+0x32/0x40
[  100.301808]  do_syscall_64+0x1a/0x90
[  100.304748]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[  100.307775] RIP: 0033:0x7f686c75c1cb
[  100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48
[  100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021
[  100.321200] RAX: ffffffffffffffda RBX: 000055f566469ea0 RCX: 00007f686c75c1cb
[  100.324631] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000000a
[  100.328104] RBP: 00007ffc60137ac0 R08: 00007f686c818460 R09: 000000000000000a
[  100.331509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
[  100.334992] R13: 0000000000000007 R14: 000000000000000a R15: 0000000000000007
[  100.338381]  </TASK>

We hit the bug because when second hist trigger has was created
has_hist_vars() returned false because hist trigger did not have
variables. As a result of that save_hist_vars() was not called to add
the trigger to trace_array->hist_vars. Later on when we attempted to
remove the first histogram find_any_var_ref() failed to detect it is
being used because it did not find the second trigger in hist_vars list.

With this change we wait until trigger actions are created so we can take
into consideration if hist trigger has variable references. Also, now we
check the return value of save_hist_vars() and fail trigger creation if
save_hist_vars() fails.

Link: https://lore.kernel.org/linux-trace-kernel/20230712223021.636335-1-mkhalfella@purestorage.com

Cc: stable@vger.kernel.org
Fixes: 067fe038e7 ("tracing: Add variable reference handling to hist triggers")
Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:37:38 +02:00
arch powerpc: Fail build if using recordmcount with binutils v2.37 2023-07-27 08:37:34 +02:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs
crypto
Documentation fs: Lock moved directories 2023-07-27 08:37:26 +02:00
drivers tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk 2023-07-27 08:37:38 +02:00
fs ceph: don't let check_caps skip sending responses for revoke msgs 2023-07-27 08:37:38 +02:00
include Revert "8250: add support for ASIX devices with a FIFO bug" 2023-07-27 08:37:38 +02:00
init
ipc
kernel tracing/histograms: Add histograms to hist_vars if they have referenced variables 2023-07-27 08:37:38 +02:00
lib
LICENSES
mm
net SUNRPC: Fix UAF in svc_tcp_listen_data_ready() 2023-07-27 08:37:35 +02:00
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.