[ Upstream commit f37c3bbc63 ]
Since referencing user space pointers is special, if the user wants to
filter on a field that is a pointer to user space, then they need to
specify it.
Add a ".ustring" attribute to the field name for filters to state that the
field is pointing to user space such that the kernel can take the
appropriate action to read that pointer.
Link: https://lore.kernel.org/all/yt9d8rvmt2jq.fsf@linux.ibm.com/
Fixes: 77360f9bbc ("tracing: Add test for user space strings when filtering on string pointers")
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 77360f9bbc ]
Pingfan reported that the following causes a fault:
echo "filename ~ \"cpu\"" > events/syscalls/sys_enter_openat/filter
echo 1 > events/syscalls/sys_enter_at/enable
The reason is that trace event filter treats the user space pointer
defined by "filename" as a normal pointer to compare against the "cpu"
string. The following bug happened:
kvm-03-guest16 login: [72198.026181] BUG: unable to handle page fault for address: 00007fffaae8ef60
#PF: supervisor read access in kernel mode
#PF: error_code(0x0001) - permissions violation
PGD 80000001008b7067 P4D 80000001008b7067 PUD 2393f1067 PMD 2393ec067 PTE 8000000108f47867
Oops: 0001 [#1] PREEMPT SMP PTI
CPU: 1 PID: 1 Comm: systemd Kdump: loaded Not tainted 5.14.0-32.el9.x86_64 #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:strlen+0x0/0x20
Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11
48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8
48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31
RSP: 0018:ffffb5b900013e48 EFLAGS: 00010246
RAX: 0000000000000018 RBX: ffff8fc1c49ede00 RCX: 0000000000000000
RDX: 0000000000000020 RSI: ffff8fc1c02d601c RDI: 00007fffaae8ef60
RBP: 00007fffaae8ef60 R08: 0005034f4ddb8ea4 R09: 0000000000000000
R10: ffff8fc1c02d601c R11: 0000000000000000 R12: ffff8fc1c8a6e380
R13: 0000000000000000 R14: ffff8fc1c02d6010 R15: ffff8fc1c00453c0
FS: 00007fa86123db40(0000) GS:ffff8fc2ffd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffaae8ef60 CR3: 0000000102880001 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
filter_pred_pchar+0x18/0x40
filter_match_preds+0x31/0x70
ftrace_syscall_enter+0x27a/0x2c0
syscall_trace_enter.constprop.0+0x1aa/0x1d0
do_syscall_64+0x16/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fa861d88664
The above happened because the kernel tried to access user space directly
and triggered a "supervisor read access in kernel mode" fault. Worse yet,
the memory could not even be loaded yet, and a SEGFAULT could happen as
well. This could be true for kernel space accessing as well.
To be even more robust, test both kernel and user space strings. If the
string fails to read, then simply have the filter fail.
Note, TASK_SIZE is used to determine if the pointer is user or kernel space
and the appropriate strncpy_from_kernel/user_nofault() function is used to
copy the memory. For some architectures, the compare to TASK_SIZE may always
pick user space or kernel space. If it gets it wrong, the only thing is that
the filter will fail to match. In the future, this needs to be fixed to have
the event denote which should be used. But failing a filter is much better
than panicing the machine, and that can be solved later.
Link: https://lore.kernel.org/all/20220107044951.22080-1-kernelfans@gmail.com/
Link: https://lkml.kernel.org/r/20220110115532.536088fd@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Reported-by: Pingfan Liu <kernelfans@gmail.com>
Tested-by: Pingfan Liu <kernelfans@gmail.com>
Fixes: 87a342f5db ("tracing/filters: Support filtering for char * strings")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1e3bac71c5 upstream.
Currently the histogram logic allows the user to write "cpu" in as an
event field, and it will record the CPU that the event happened on.
The problem with this is that there's a lot of events that have "cpu"
as a real field, and using "cpu" as the CPU it ran on, makes it
impossible to run histograms on the "cpu" field of events.
For example, if I want to have a histogram on the count of the
workqueue_queue_work event on its cpu field, running:
># echo 'hist:keys=cpu' > events/workqueue/workqueue_queue_work/trigger
Gives a misleading and wrong result.
Change the command to "common_cpu" as no event should have "common_*"
fields as that's a reserved name for fields used by all events. And
this makes sense here as common_cpu would be a field used by all events.
Now we can even do:
># echo 'hist:keys=common_cpu,cpu if cpu < 100' > events/workqueue/workqueue_queue_work/trigger
># cat events/workqueue/workqueue_queue_work/hist
# event histogram
#
# trigger info: hist:keys=common_cpu,cpu:vals=hitcount:sort=hitcount:size=2048 if cpu < 100 [active]
#
{ common_cpu: 0, cpu: 2 } hitcount: 1
{ common_cpu: 0, cpu: 4 } hitcount: 1
{ common_cpu: 7, cpu: 7 } hitcount: 1
{ common_cpu: 0, cpu: 7 } hitcount: 1
{ common_cpu: 0, cpu: 1 } hitcount: 1
{ common_cpu: 0, cpu: 6 } hitcount: 2
{ common_cpu: 0, cpu: 5 } hitcount: 2
{ common_cpu: 1, cpu: 1 } hitcount: 4
{ common_cpu: 6, cpu: 6 } hitcount: 4
{ common_cpu: 5, cpu: 5 } hitcount: 14
{ common_cpu: 4, cpu: 4 } hitcount: 26
{ common_cpu: 0, cpu: 0 } hitcount: 39
{ common_cpu: 2, cpu: 2 } hitcount: 184
Now for backward compatibility, I added a trick. If "cpu" is used, and
the field is not found, it will fall back to "common_cpu" and work as
it did before. This way, it will still work for old programs that use
"cpu" to get the actual CPU, but if the event has a "cpu" as a field, it
will get that event's "cpu" field, which is probably what it wants
anyway.
I updated the tracefs/README to include documentation about both the
common_timestamp and the common_cpu. This way, if that text is present in
the README, then an application can know that common_cpu is supported over
just plain "cpu".
Link: https://lkml.kernel.org/r/20210721110053.26b4f641@oasis.local.home
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 8b7622bf94 ("tracing: Add cpu field for hist triggers")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c25ce589dc upstream.
Change every shebang which does not need an argument to use /usr/bin/env.
This is needed as not every distro has everything under /usr/bin,
sometimes not even bash.
Signed-off-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull documentation updates from Mauro Carvalho Chehab:
"A series of patches addressing warnings produced by make htmldocs.
This includes:
- kernel-doc markup fixes
- ReST fixes
- Updates at the build system in order to support newer versions of
the docs build toolchain (Sphinx)
After this series, the number of html build warnings should reduce
significantly, and building with Sphinx 3.1 or later should now be
supported (although it is still recommended to use Sphinx 2.4.4).
As agreed with Jon, I should be sending you a late pull request by the
end of the merge window addressing remaining issues with docs build,
as there are a number of warning fixes that depends on pull requests
that should be happening along the merge window.
The end goal is to have a clean htmldocs build on Kernel 5.10.
PS. It should be noticed that Sphinx 3.0 is not currently supported,
as it lacks support for C domain namespaces. Such feature, needed in
order to document uAPI system calls with Sphinx 3.x, was added only on
Sphinx 3.1"
* tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (75 commits)
PM / devfreq: remove a duplicated kernel-doc markup
mm/doc: fix a literal block markup
workqueue: fix a kernel-doc warning
docs: virt: user_mode_linux_howto_v2.rst: fix a literal block markup
Input: sparse-keymap: add a description for @sw
rcu/tree: docs: document bkvcache new members at struct kfree_rcu_cpu
nl80211: docs: add a description for s1g_cap parameter
usb: docs: document altmode register/unregister functions
kunit: test.h: fix a bad kernel-doc markup
drivers: core: fix kernel-doc markup for dev_err_probe()
docs: bio: fix a kerneldoc markup
kunit: test.h: solve kernel-doc warnings
block: bio: fix a warning at the kernel-doc markups
docs: powerpc: syscall64-abi.rst: fix a malformed table
drivers: net: hamradio: fix document location
net: appletalk: Kconfig: Fix docs location
dt-bindings: fix references to files converted to yaml
memblock: get rid of a :c:type leftover
math64.h: kernel-docs: Convert some markups into normal comments
media: uAPI: buffer.rst: remove a left-over documentation
...
Pull tracing updates from Steven Rostedt:
"Updates for tracing and bootconfig:
- Add support for "bool" type in synthetic events
- Add per instance tracing for bootconfig
- Support perf-style return probe ("SYMBOL%return") in kprobes and
uprobes
- Allow for kprobes to be enabled earlier in boot up
- Added tracepoint helper function to allow testing if tracepoints
are enabled in headers
- Synthetic events can now have dynamic strings (variable length)
- Various fixes and cleanups"
* tag 'trace-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (58 commits)
tracing: support "bool" type in synthetic trace events
selftests/ftrace: Add test case for synthetic event syntax errors
tracing: Handle synthetic event array field type checking correctly
selftests/ftrace: Change synthetic event name for inter-event-combined test
tracing: Add synthetic event error logging
tracing: Check that the synthetic event and field names are legal
tracing: Move is_good_name() from trace_probe.h to trace.h
tracing: Don't show dynamic string internals in synthetic event description
tracing: Fix some typos in comments
tracing/boot: Add ftrace.instance.*.alloc_snapshot option
tracing: Fix race in trace_open and buffer resize call
tracing: Check return value of __create_val_fields() before using its result
tracing: Fix synthetic print fmt check for use of __get_str()
tracing: Remove a pointless assignment
ftrace: ftrace_global_list is renamed to ftrace_ops_list
ftrace: Format variable declarations of ftrace_allocate_records
ftrace: Simplify the calculation of page number for ftrace_page->records
ftrace: Simplify the dyn_ftrace->flags macro
ftrace: Simplify the hash calculation
ftrace: Use fls() to get the bits for dup_hash()
...
There are some c-domain tags that are wrong. While this won't
cause problems with Sphinx < 3.0, this cause troubles with
newer versions, as the C parser won't recognize the contents
of the tag, and will drop it from the output.
Let's just place them at literal blocks.
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Pull kernel_clone() updates from Christian Brauner:
"During the v5.9 merge window we reworked the process creation
codepaths across multiple architectures. After this work we were only
left with the _do_fork() helper based on the struct kernel_clone_args
calling convention. As was pointed out _do_fork() isn't valid
kernelese especially for a helper that isn't just static.
This series removes the _do_fork() helper and introduces the new
kernel_clone() helper. The process creation cleanup didn't change the
name to something more reasonable mainly because _do_fork() was used
in quite a few places. So sending this as a separate series seemed the
better strategy.
I originally intended to send this early in the v5.9 development cycle
after the merge window had closed but given that this was touching
quite a few places I decided to defer this until the v5.10 merge
window"
* tag 'kernel-clone-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
sched: remove _do_fork()
tracing: switch to kernel_clone()
kgdbts: switch to kernel_clone()
kprobes: switch to kernel_clone()
x86: switch to kernel_clone()
sparc: switch to kernel_clone()
nios2: switch to kernel_clone()
m68k: switch to kernel_clone()
ia64: switch to kernel_clone()
h8300: switch to kernel_clone()
fork: introduce kernel_clone()
Currently, sythetic events only support static string fields such as:
# echo 'test_latency u64 lat; char somename[32]' > /sys/kernel/debug/tracing/synthetic_events
Which is fine, but wastes a lot of space in the event.
It also prevents the most commonly-defined strings in the existing
trace events e.g. those defined using __string(), from being passed to
synthetic events via the trace() action.
With this change, synthetic events with dynamic fields can be defined:
# echo 'test_latency u64 lat; char somename[]' > /sys/kernel/debug/tracing/synthetic_events
And the trace() action can be used to generate events using either
dynamic or static strings:
# echo 'hist:keys=name:lat=common_timestamp.usecs-$ts0:onmatch(sys.event).test_latency($lat,name)' > /sys/kernel/debug/tracing/events
The synthetic event dynamic strings are implemented in the same way as
the existing __data_loc strings and appear as such in the format file.
[ <rostedt@goodmis.org>: added __set_synth_event_print_fmt() changes:
I added the following to make it work with trace-cmd. Dynamic strings
must have __get_str() for events in the print_fmt otherwise it can't be
parsed correctly. ]
Link: https://lore.kernel.org/r/cover.1601588066.git.zanussi@kernel.org
Link: https://lkml.kernel.org/r/3ed35b6d0e390f5b94cb4a9ba1cc18f5982ab277.1601848695.git.zanussi@kernel.org
Tested-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As tracepoints are discouraged from being added in a header because it can
cause side effects if other tracepoints are in headers, as well as bloat the
kernel as the trace_<tracepoint>() function is not a small inline, the common
workaround is to add a function call that calls a wrapper function in a
C file that then calls the tracepoint. But as function calls add overhead,
this function should only be called when the tracepoint in question is
enabled. To get around this overhead, a static_branch can be used to only
have the tracepoint wrapper get called when the tracepoint is enabled.
Add a tracepoint_enabled(tp) macro that gets passed the name of the
tracepoint, and this becomes a static_branch that is enabled when the
tracepoint is enabled and is a nop when the tracepoint is disabled.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull documentation fixes from Jonathan Corbet:
"A handful of obvious fixes that wandered in during the merge window"
* tag 'docs-5.9-2' of git://git.lwn.net/linux:
Documentation/locking/locktypes: fix the typo
doc/zh_CN: resolve undefined label warning in admin-guide index
doc/zh_CN: fix title heading markup in admin-guide cpu-load
docs: remove the 2.6 "Upgrading I2C Drivers" guide
docs: Correct the release date of 5.2 stable
mailmap: Update comments for with format and more detalis
docs: cdrom: Fix a typo and rst markup
Doc: admin-guide: use correct legends in kernel-parameters.txt
Documentation/features: refresh RISC-V arch support files
documentation: coccinelle: Improve command example for make C={1,2}
Core-api: Documentation: Replace deprecated :c:func: Usage
Dev-tools: Documentation: Replace deprecated :c:func: Usage
Filesystems: Documentation: Replace deprecated :c:func: Usage
docs: trace: fix a typo
Pull documentation updates from Jonathan Corbet:
"It's been a busy cycle for documentation - hopefully the busiest for a
while to come. Changes include:
- Some new Chinese translations
- Progress on the battle against double words words and non-HTTPS
URLs
- Some block-mq documentation
- More RST conversions from Mauro. At this point, that task is
essentially complete, so we shouldn't see this kind of churn again
for a while. Unless we decide to switch to asciidoc or
something...:)
- Lots of typo fixes, warning fixes, and more"
* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
scripts/kernel-doc: optionally treat warnings as errors
docs: ia64: correct typo
mailmap: add entry for <alobakin@marvell.com>
doc/zh_CN: add cpu-load Chinese version
Documentation/admin-guide: tainted-kernels: fix spelling mistake
MAINTAINERS: adjust kprobes.rst entry to new location
devices.txt: document rfkill allocation
PCI: correct flag name
docs: filesystems: vfs: correct flag name
docs: filesystems: vfs: correct sync_mode flag names
docs: path-lookup: markup fixes for emphasis
docs: path-lookup: more markup fixes
docs: path-lookup: fix HTML entity mojibake
CREDITS: Replace HTTP links with HTTPS ones
docs: process: Add an example for creating a fixes tag
doc/zh_CN: add Chinese translation prefer section
doc/zh_CN: add clearing-warn-once Chinese version
doc/zh_CN: add admin-guide index
doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
futex: MAINTAINERS: Re-add selftests directory
...
