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2023-09-13Merge tag 'trace-v6.6-rc1' of ↵Linus Torvalds1-9/+63
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Add missing LOCKDOWN checks for eventfs callers When LOCKDOWN is active for tracing, it causes inconsistent state when some functions succeed and others fail. - Use dput() to free the top level eventfs descriptor There was a race between accesses and freeing it. - Fix a long standing bug that eventfs exposed due to changing timings by dynamically creating files. That is, If a event file is opened for an instance, there's nothing preventing the instance from being removed which will make accessing the files cause use-after-free bugs. - Fix a ring buffer race that happens when iterating over the ring buffer while writers are active. Check to make sure not to read the event meta data if it's beyond the end of the ring buffer sub buffer. - Fix the print trigger that disappeared because the test to create it was looking for the event dir field being filled, but now it has the "ef" field filled for the eventfs structure. - Remove the unused "dir" field from the event structure. - Fix the order of the trace_dynamic_info as it had it backwards for the offset and len fields for which one was for which endianess. - Fix NULL pointer dereference with eventfs_remove_rec() If an allocation fails in one of the eventfs_add_*() functions, the caller of it in event_subsystem_dir() or event_create_dir() assigns the result to the structure. But it's assigning the ERR_PTR and not NULL. This was passed to eventfs_remove_rec() which expects either a good pointer or a NULL, not ERR_PTR. The fix is to not assign the ERR_PTR to the structure, but to keep it NULL on error. - Fix list_for_each_rcu() to use list_for_each_srcu() in dcache_dir_open_wrapper(). One iteration of the code used RCU but because it had to call sleepable code, it had to be changed to use SRCU, but one of the iterations was missed. - Fix synthetic event print function to use "as_u64" instead of passing in a pointer to the union. To fix big/little endian issues, the u64 that represented several types was turned into a union to define the types properly. * tag 'trace-v6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec() tracefs/eventfs: Use list_for_each_srcu() in dcache_dir_open_wrapper() tracing/synthetic: Print out u64 values properly tracing/synthetic: Fix order of struct trace_dynamic_info selftests/ftrace: Fix dependencies for some of the synthetic event tests tracing: Remove unused trace_event_file dir field tracing: Use the new eventfs descriptor for print trigger ring-buffer: Do not attempt to read past "commit" tracefs/eventfs: Free top level files on removal ring-buffer: Avoid softlockup in ring_buffer_resize() tracing: Have event inject files inc the trace array ref count tracing: Have option files inc the trace array ref count tracing: Have current_trace inc the trace array ref count tracing: Have tracing_max_latency inc the trace array ref count tracing: Increase trace array ref count on enable and filter files tracefs/eventfs: Use dput to free the toplevel events directory tracefs/eventfs: Add missing lockdown checks tracefs: Add missing lockdown check to tracefs_create_dir()
2023-09-08tracing: Use the new eventfs descriptor for print triggerSteven Rostedt (Google)1-2/+2
The check to create the print event "trigger" was using the obsolete "dir" value of the trace_event_file to determine if it should create the trigger or not. But that value will now be NULL because it uses the event file descriptor. Change it to test the "ef" field of the trace_event_file structure so that the trace_marker "trigger" file appears again. Link: https://lkml.kernel.org/r/20230908022001.371815239@goodmis.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ajay Kaher <akaher@vmware.com> Fixes: 27152bceea1df ("eventfs: Move tracing/events to eventfs") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07tracing: Have option files inc the trace array ref countSteven Rostedt (Google)1-1/+22
The option files update the options for a given trace array. For an instance, if the file is opened and the instance is deleted, reading or writing to the file will cause a use after free. Up the ref count of the trace_array when an option file is opened. Link: https://lkml.kernel.org/r/20230907024804.086679464@goodmis.org Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Zheng Yejian <zhengyejian1@huawei.com> Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()") Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07tracing: Have current_trace inc the trace array ref countSteven Rostedt (Google)1-1/+2
The current_trace updates the trace array tracer. For an instance, if the file is opened and the instance is deleted, reading or writing to the file will cause a use after free. Up the ref count of the trace array when current_trace is opened. Link: https://lkml.kernel.org/r/20230907024803.877687227@goodmis.org Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Zheng Yejian <zhengyejian1@huawei.com> Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()") Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07tracing: Have tracing_max_latency inc the trace array ref countSteven Rostedt (Google)1-5/+10
The tracing_max_latency file points to the trace_array max_latency field. For an instance, if the file is opened and the instance is deleted, reading or writing to the file will cause a use after free. Up the ref count of the trace_array when tracing_max_latency is opened. Link: https://lkml.kernel.org/r/20230907024803.666889383@goodmis.org Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Zheng Yejian <zhengyejian1@huawei.com> Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()") Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07tracing: Increase trace array ref count on enable and filter filesSteven Rostedt (Google)1-0/+27
When the trace event enable and filter files are opened, increment the trace array ref counter, otherwise they can be accessed when the trace array is being deleted. The ref counter keeps the trace array from being deleted while those files are opened. Link: https://lkml.kernel.org/r/20230907024803.456187066@goodmis.org Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()") Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reported-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-02Merge tag 'probes-v6.6' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull probes updates from Masami Hiramatsu: - kprobes: use struct_size() for variable size kretprobe_instance data structure. - eprobe: Simplify trace_eprobe list iteration. - probe events: Data structure field access support on BTF argument. - Update BTF argument support on the functions in the kernel loadable modules (only loaded modules are supported). - Move generic BTF access function (search function prototype and get function parameters) to a separated file. - Add a function to search a member of data structure in BTF. - Support accessing BTF data structure member from probe args by C-like arrow('->') and dot('.') operators. e.g. 't sched_switch next=next->pid vruntime=next->se.vruntime' - Support accessing BTF data structure member from $retval. e.g. 'f getname_flags%return +0($retval->name):string' - Add string type checking if BTF type info is available. This will reject if user specify ":string" type for non "char pointer" type. - Automatically assume the fprobe event as a function return event if $retval is used. - selftests/ftrace: Add BTF data field access test cases. - Documentation: Update fprobe event example with BTF data field. * tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: Documentation: tracing: Update fprobe event example with BTF field selftests/ftrace: Add BTF fields access testcases tracing/fprobe-event: Assume fprobe is a return event by $retval tracing/probes: Add string type check with BTF tracing/probes: Support BTF field access from $retval tracing/probes: Support BTF based data structure field access tracing/probes: Add a function to search a member of a struct/union tracing/probes: Move finding func-proto API and getting func-param API to trace_btf tracing/probes: Support BTF argument on module functions tracing/eprobe: Iterate trace_eprobe directly kernel: kprobes: Use struct_size()
2023-09-01tracing: Zero the pipe cpumask on alloc to avoid spurious -EBUSYBrian Foster1-2/+2
The pipe cpumask used to serialize opens between the main and percpu trace pipes is not zeroed or initialized. This can result in spurious -EBUSY returns if underlying memory is not fully zeroed. This has been observed by immediate failure to read the main trace_pipe file on an otherwise newly booted and idle system: # cat /sys/kernel/debug/tracing/trace_pipe cat: /sys/kernel/debug/tracing/trace_pipe: Device or resource busy Zero the allocation of pipe_cpumask to avoid the problem. Link: https://lore.kernel.org/linux-trace-kernel/20230831125500.986862-1-bfoster@redhat.com Cc: stable@vger.kernel.org Fixes: c2489bb7e6be ("tracing: Introduce pipe_cpumask to avoid race on trace_pipes") Reviewed-by: Zheng Yejian <zhengyejian1@huawei.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-01tracing: Fix race issue between cpu buffer write and swapZheng Yejian1-5/+12
Warning happened in rb_end_commit() at code: if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))) WARNING: CPU: 0 PID: 139 at kernel/trace/ring_buffer.c:3142 rb_commit+0x402/0x4a0 Call Trace: ring_buffer_unlock_commit+0x42/0x250 trace_buffer_unlock_commit_regs+0x3b/0x250 trace_event_buffer_commit+0xe5/0x440 trace_event_buffer_reserve+0x11c/0x150 trace_event_raw_event_sched_switch+0x23c/0x2c0 __traceiter_sched_switch+0x59/0x80 __schedule+0x72b/0x1580 schedule+0x92/0x120 worker_thread+0xa0/0x6f0 It is because the race between writing event into cpu buffer and swapping cpu buffer through file per_cpu/cpu0/snapshot: Write on CPU 0 Swap buffer by per_cpu/cpu0/snapshot on CPU 1 -------- -------- tracing_snapshot_write() [...] ring_buffer_lock_reserve() cpu_buffer = buffer->buffers[cpu]; // 1. Suppose find 'cpu_buffer_a'; [...] rb_reserve_next_event() [...] ring_buffer_swap_cpu() if (local_read(&cpu_buffer_a->committing)) goto out_dec; if (local_read(&cpu_buffer_b->committing)) goto out_dec; buffer_a->buffers[cpu] = cpu_buffer_b; buffer_b->buffers[cpu] = cpu_buffer_a; // 2. cpu_buffer has swapped here. rb_start_commit(cpu_buffer); if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) { // 3. This check passed due to 'cpu_buffer->buffer' [...] // has not changed here. return NULL; } cpu_buffer_b->buffer = buffer_a; cpu_buffer_a->buffer = buffer_b; [...] // 4. Reserve event from 'cpu_buffer_a'. ring_buffer_unlock_commit() [...] cpu_buffer = buffer->buffers[cpu]; // 5. Now find 'cpu_buffer_b' !!! rb_commit(cpu_buffer) rb_end_commit() // 6. WARN for the wrong 'committing' state !!! Based on above analysis, we can easily reproduce by following testcase: ``` bash #!/bin/bash dmesg -n 7 sysctl -w kernel.panic_on_warn=1 TR=/sys/kernel/tracing echo 7 > ${TR}/buffer_size_kb echo "sched:sched_switch" > ${TR}/set_event while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & ``` To fix it, IIUC, we can use smp_call_function_single() to do the swap on the target cpu where the buffer is located, so that above race would be avoided. Link: https://lore.kernel.org/linux-trace-kernel/20230831132739.4070878-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Fixes: f1affcaaa861 ("tracing: Add snapshot in the per_cpu trace directories") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-01Merge tag 'trace-v6.6' of ↵Linus Torvalds1-59/+40
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: "User visible changes: - Added a way to easier filter with cpumasks: # echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter - Show actual size of ring buffer after modifying the ring buffer size via buffer_size_kb. Currently it just returns what was written, but the actual size rounds up to the sub buffer size. Show that real size instead. Major changes: - Added "eventfs". This is the code that handles the inodes and dentries of tracefs/events directory. As there are thousands of events, and each event has several inodes and dentries that currently exist even when tracing is never used, they take up precious memory. Instead, eventfs will allocate the inodes and dentries in a JIT way (similar to what procfs does). There is now metadata that handles the events and subdirectories, and will create the inodes and dentries when they are used. Note, I also have patches that remove the subdirectory meta data, but will wait till the next merge window before applying them. It's a little more complex, and I want to make sure the dynamic code works properly before adding more complexity, making it easier to revert if need be. Minor changes: - Optimization to user event list traversal - Remove intermediate permission of tracefs files (note the intermediate permission removes all access to the files so it is not a security concern, but just a clean up) - Add the complex fix to FORTIFY_SOURCE to the kernel stack event logic - Other minor cleanups" * tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits) tracefs: Remove kerneldoc from struct eventfs_file tracefs: Avoid changing i_mode to a temp value tracing/user_events: Optimize safe list traversals ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon() tracing: Remove unused function declarations tracing/filters: Document cpumask filtering tracing/filters: Further optimise scalar vs cpumask comparison tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU tracing/filters: Enable filtering the CPU common field by a cpumask tracing/filters: Enable filtering a scalar field by a cpumask tracing/filters: Enable filtering a cpumask field by another cpumask tracing/filters: Dynamically allocate filter_pred.regex test: ftrace: Fix kprobe test for eventfs eventfs: Move tracing/events to eventfs eventfs: Implement removal of meta data from eventfs eventfs: Implement functions to create files and dirs when accessed eventfs: Implement eventfs lookup, read, open functions eventfs: Implement eventfs file add functions ...
2023-08-23tracing/probes: Support BTF based data structure field accessMasami Hiramatsu (Google)1-1/+2
Using BTF to access the fields of a data structure. You can use this for accessing the field with '->' or '.' operation with BTF argument. # echo 't sched_switch next=next->pid vruntime=next->se.vruntime' \ > dynamic_events # echo 1 > events/tracepoints/sched_switch/enable # head -n 40 trace | tail <idle>-0 [000] d..3. 272.565382: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956533179 kcompactd0-26 [000] d..3. 272.565406: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 <idle>-0 [000] d..3. 273.069441: sched_switch: (__probestub_sched_switch+0x4/0x10) next=9 vruntime=956533179 kworker/0:1-9 [000] d..3. 273.069464: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956579181 kcompactd0-26 [000] d..3. 273.069480: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 <idle>-0 [000] d..3. 273.141434: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956533179 kworker/u2:1-22 [000] d..3. 273.141461: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 <idle>-0 [000] d..3. 273.480872: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956585857 kworker/u2:1-22 [000] d..3. 273.480905: sched_switch: (__probestub_sched_switch+0x4/0x10) next=70 vruntime=959533179 sh-70 [000] d..3. 273.481102: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 Link: https://lore.kernel.org/all/169272157251.160970.9318175874130965571.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-21tracing: Introduce pipe_cpumask to avoid race on trace_pipesZheng Yejian1-7/+48
There is race issue when concurrently splice_read main trace_pipe and per_cpu trace_pipes which will result in data read out being different from what actually writen. As suggested by Steven: > I believe we should add a ref count to trace_pipe and the per_cpu > trace_pipes, where if they are opened, nothing else can read it. > > Opening trace_pipe locks all per_cpu ref counts, if any of them are > open, then the trace_pipe open will fail (and releases any ref counts > it had taken). > > Opening a per_cpu trace_pipe will up the ref count for just that > CPU buffer. This will allow multiple tasks to read different per_cpu > trace_pipe files, but will prevent the main trace_pipe file from > being opened. But because we only need to know whether per_cpu trace_pipe is open or not, using a cpumask instead of using ref count may be easier. After this patch, users will find that: - Main trace_pipe can be opened by only one user, and if it is opened, all per_cpu trace_pipes cannot be opened; - Per_cpu trace_pipes can be opened by multiple users, but each per_cpu trace_pipe can only be opened by one user. And if one of them is opened, main trace_pipe cannot be opened. Link: https://lore.kernel.org/linux-trace-kernel/20230818022645.1948314-1-zhengyejian1@huawei.com Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-17tracing: Fix memleak due to race between current_tracer and traceZheng Yejian1-1/+8
Kmemleak report a leak in graph_trace_open(): unreferenced object 0xffff0040b95f4a00 (size 128): comm "cat", pid 204981, jiffies 4301155872 (age 99771.964s) hex dump (first 32 bytes): e0 05 e7 b4 ab 7d 00 00 0b 00 01 00 00 00 00 00 .....}.......... f4 00 01 10 00 a0 ff ff 00 00 00 00 65 00 10 00 ............e... backtrace: [<000000005db27c8b>] kmem_cache_alloc_trace+0x348/0x5f0 [<000000007df90faa>] graph_trace_open+0xb0/0x344 [<00000000737524cd>] __tracing_open+0x450/0xb10 [<0000000098043327>] tracing_open+0x1a0/0x2a0 [<00000000291c3876>] do_dentry_open+0x3c0/0xdc0 [<000000004015bcd6>] vfs_open+0x98/0xd0 [<000000002b5f60c9>] do_open+0x520/0x8d0 [<00000000376c7820>] path_openat+0x1c0/0x3e0 [<00000000336a54b5>] do_filp_open+0x14c/0x324 [<000000002802df13>] do_sys_openat2+0x2c4/0x530 [<0000000094eea458>] __arm64_sys_openat+0x130/0x1c4 [<00000000a71d7881>] el0_svc_common.constprop.0+0xfc/0x394 [<00000000313647bf>] do_el0_svc+0xac/0xec [<000000002ef1c651>] el0_svc+0x20/0x30 [<000000002fd4692a>] el0_sync_handler+0xb0/0xb4 [<000000000c309c35>] el0_sync+0x160/0x180 The root cause is descripted as follows: __tracing_open() { // 1. File 'trace' is being opened; ... *iter->trace = *tr->current_trace; // 2. Tracer 'function_graph' is // currently set; ... iter->trace->open(iter); // 3. Call graph_trace_open() here, // and memory are allocated in it; ... } s_start() { // 4. The opened file is being read; ... *iter->trace = *tr->current_trace; // 5. If tracer is switched to // 'nop' or others, then memory // in step 3 are leaked!!! ... } To fix it, in s_start(), close tracer before switching then reopen the new tracer after switching. And some tracers like 'wakeup' may not update 'iter->private' in some cases when reopen, then it should be cleared to avoid being mistakenly closed again. Link: https://lore.kernel.org/linux-trace-kernel/20230817125539.1646321-1-zhengyejian1@huawei.com Fixes: d7350c3f4569 ("tracing/core: make the read callbacks reentrants") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-16tracing: Fix cpu buffers unavailable due to 'record_disabled' missedZheng Yejian1-0/+6
Trace ring buffer can no longer record anything after executing following commands at the shell prompt: # cd /sys/kernel/tracing # cat tracing_cpumask fff # echo 0 > tracing_cpumask # echo 1 > snapshot # echo fff > tracing_cpumask # echo 1 > tracing_on # echo "hello world" > trace_marker -bash: echo: write error: Bad file descriptor The root cause is that: 1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask()); 2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped with 'tr->max_buffer.buffer', then the 'record_disabled' became 0 (see update_max_tr()); 3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1; Then array_buffer and max_buffer are both unavailable due to value of 'record_disabled' is not 0. To fix it, enable or disable both array_buffer and max_buffer at the same time in tracing_set_cpumask(). Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Cc: <vnagarnaik@google.com> Cc: <shuah@kernel.org> Fixes: 71babb2705e2 ("tracing: change CPU ring buffer state from tracing_cpumask") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30tracing: Set actual size after ring buffer resizeZheng Yejian1-8/+11
Currently we can resize trace ringbuffer by writing a value into file 'buffer_size_kb', then by reading the file, we get the value that is usually what we wrote. However, this value may be not actual size of trace ring buffer because of the round up when doing resize in kernel, and the actual size would be more useful. Link: https://lore.kernel.org/linux-trace-kernel/20230705002705.576633-1-zhengyejian1@huawei.com Cc: <mhiramat@kernel.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30tracing: Add free_trace_iter_content() helper functionSteven Rostedt (Google)1-11/+22
As the trace iterator is created and used by various interfaces, the clean up of it needs to be consistent. Create a free_trace_iter_content() helper function that frees the content of the iterator and use that to clean it up in all places that it is used. Link: https://lkml.kernel.org/r/20230715141348.341887497@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30tracing: Remove unnecessary copying of tr->current_traceSteven Rostedt (Google)1-19/+3
The iterator allocated a descriptor to copy the current_trace. This was done with the assumption that the function pointers might change. But this was a false assuption, as it does not change. There's no reason to make a copy of the current_trace and just use the pointer it points to. This removes needing to manage freeing the descriptor. Worse yet, there's locations that the iterator is used but does make a copy and just uses the pointer. This could cause the actual pointer to the trace descriptor to be freed and not the allocated copy. This is more of a clean up than a fix. Link: https://lkml.kernel.org/r/20230715141348.135792275@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: d7350c3f45694 ("tracing/core: make the read callbacks reentrants") Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structureSteven Rostedt (Google)1-21/+4
For backward compatibility, older tooling expects to see the kernel_stack event with a "caller" field that is a fixed size array of 8 addresses. The code now supports more than 8 with an added "size" field that states the real number of entries. But the "caller" field still just looks like a fixed size to user space. Since the tracing macros that create the user space format files also creates the structures that those files represent, the kernel_stack event structure had its "caller" field a fixed size of 8, but in reality, when it is allocated on the ring buffer, it can hold more if the stack trace is bigger that 8 functions. The copying of these entries was simply done with a memcpy(): size = nr_entries * sizeof(unsigned long); memcpy(entry->caller, fstack->calls, size); The FORTIFY_SOURCE logic noticed at runtime that when the nr_entries was larger than 8, that the memcpy() was writing more than what the structure stated it can hold and it complained about it. This is because the FORTIFY_SOURCE code is unaware that the amount allocated is actually enough to hold the size. It does not expect that a fixed size field will hold more than the fixed size. This was originally solved by hiding the caller assignment with some pointer arithmetic. ptr = ring_buffer_data(); entry = ptr; ptr += offsetof(typeof(*entry), caller); memcpy(ptr, fstack->calls, size); But it is considered bad form to hide from kernel hardening. Instead, make it work nicely with FORTIFY_SOURCE by adding a new __stack_array() macro that is specific for this one special use case. The macro will take 4 arguments: type, item, len, field (whereas the __array() macro takes just the first three). This macro will act just like the __array() macro when creating the code to deal with the format file that is exposed to user space. But for the kernel, it will turn the caller field into: type item[] __counted_by(field); or for this instance: unsigned long caller[] __counted_by(size); Now the kernel code can expose the assignment of the caller to the FORTIFY_SOURCE and everyone is happy! Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20230713092605.2ddb9788@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Reviewed-by: Kees Cook <keescook@chromium.org>
2023-07-23ring-buffer: Do not swap cpu_buffer during resize processChen Lin1-1/+2
When ring_buffer_swap_cpu was called during resize process, the cpu buffer was swapped in the middle, resulting in incorrect state. Continuing to run in the wrong state will result in oops. This issue can be easily reproduced using the following two scripts: /tmp # cat test1.sh //#! /bin/sh for i in `seq 0 100000` do echo 2000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 echo 5000 > /sys/kernel/debug/tracing/buffer_size_kb sleep 0.5 done /tmp # cat test2.sh //#! /bin/sh for i in `seq 0 100000` do echo irqsoff > /sys/kernel/debug/tracing/current_tracer sleep 1 echo nop > /sys/kernel/debug/tracing/current_tracer sleep 1 done /tmp # ./test1.sh & /tmp # ./test2.sh & A typical oops log is as follows, sometimes with other different oops logs. [ 231.711293] WARNING: CPU: 0 PID: 9 at kernel/trace/ring_buffer.c:2026 rb_update_pages+0x378/0x3f8 [ 231.713375] Modules linked in: [ 231.714735] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec23f92 #15 [ 231.716750] Hardware name: linux,dummy-virt (DT) [ 231.718152] Workqueue: events update_pages_handler [ 231.719714] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 231.721171] pc : rb_update_pages+0x378/0x3f8 [ 231.722212] lr : rb_update_pages+0x25c/0x3f8 [ 231.723248] sp : ffff800082b9bd50 [ 231.724169] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 231.726102] x26: 0000000000000001 x25: fffffffffffff010 x24: 0000000000000ff0 [ 231.728122] x23: ffff0000c3a0b600 x22: ffff0000c3a0b5c0 x21: fffffffffffffe0a [ 231.730203] x20: ffff0000c3a0b600 x19: ffff0000c0102400 x18: 0000000000000000 [ 231.732329] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffe7aa8510 [ 231.734212] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000002 [ 231.736291] x11: ffff8000826998a8 x10: ffff800082b9baf0 x9 : ffff800081137558 [ 231.738195] x8 : fffffc00030e82c8 x7 : 0000000000000000 x6 : 0000000000000001 [ 231.740192] x5 : ffff0000ffbafe00 x4 : 0000000000000000 x3 : 0000000000000000 [ 231.742118] x2 : 00000000000006aa x1 : 0000000000000001 x0 : ffff0000c0007208 [ 231.744196] Call trace: [ 231.744892] rb_update_pages+0x378/0x3f8 [ 231.745893] update_pages_handler+0x1c/0x38 [ 231.746893] process_one_work+0x1f0/0x468 [ 231.747852] worker_thread+0x54/0x410 [ 231.748737] kthread+0x124/0x138 [ 231.749549] ret_from_fork+0x10/0x20 [ 231.750434] ---[ end trace 0000000000000000 ]--- [ 233.720486] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 233.721696] Mem abort info: [ 233.721935] ESR = 0x0000000096000004 [ 233.722283] EC = 0x25: DABT (current EL), IL = 32 bits [ 233.722596] SET = 0, FnV = 0 [ 233.722805] EA = 0, S1PTW = 0 [ 233.723026] FSC = 0x04: level 0 translation fault [ 233.723458] Data abort info: [ 233.723734] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 233.724176] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 233.724589] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 233.725075] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000104943000 [ 233.725592] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 233.726231] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 233.726720] Modules linked in: [ 233.727007] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G W 6.5.0-rc1-00276-g20edcec23f92 #15 [ 233.727777] Hardware name: linux,dummy-virt (DT) [ 233.728225] Workqueue: events update_pages_handler [ 233.728655] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 233.729054] pc : rb_update_pages+0x1a8/0x3f8 [ 233.729334] lr : rb_update_pages+0x154/0x3f8 [ 233.729592] sp : ffff800082b9bd50 [ 233.729792] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000 [ 233.730220] x26: 0000000000000000 x25: ffff800082a8b840 x24: ffff0000c0102418 [ 233.730653] x23: 0000000000000000 x22: fffffc000304c880 x21: 0000000000000003 [ 233.731105] x20: 00000000000001f4 x19: ffff0000c0102400 x18: ffff800082fcbc58 [ 233.731727] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001 [ 233.732282] x14: ffff8000825fe0c8 x13: 0000000000000001 x12: 0000000000000000 [ 233.732709] x11: ffff8000826998a8 x10: 0000000000000ae0 x9 : ffff8000801b760c [ 233.733148] x8 : fefefefefefefeff x7 : 0000000000000018 x6 : ffff0000c03298c0 [ 233.733553] x5 : 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000 [ 233.733972] x2 : ffff0000c3a0b600 x1 : 0000000000000000 x0 : 0000000000000000 [ 233.734418] Call trace: [ 233.734593] rb_update_pages+0x1a8/0x3f8 [ 233.734853] update_pages_handler+0x1c/0x38 [ 233.735148] process_one_work+0x1f0/0x468 [ 233.735525] worker_thread+0x54/0x410 [ 233.735852] kthread+0x124/0x138 [ 233.736064] ret_from_fork+0x10/0x20 [ 233.736387] Code: 92400000 910006b5 aa000021 aa0303f7 (f9400060) [ 233.736959] ---[ end trace 0000000000000000 ]--- After analysis, the seq of the error is as follows [1-5]: int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu_id) { for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //1. get cpu_buffer, aka cpu_buffer(A) ... ... schedule_work_on(cpu, &cpu_buffer->update_pages_work); //2. 'update_pages_work' is queue on 'cpu', cpu_buffer(A) is passed to // update_pages_handler, do the update process, set 'update_done' in // complete(&cpu_buffer->update_done) and to wakeup resize process. //----> //3. Just at this moment, ring_buffer_swap_cpu is triggered, //cpu_buffer(A) be swaped to cpu_buffer(B), the max_buffer. //ring_buffer_swap_cpu is called as the 'Call trace' below. Call trace: dump_backtrace+0x0/0x2f8 show_stack+0x18/0x28 dump_stack+0x12c/0x188 ring_buffer_swap_cpu+0x2f8/0x328 update_max_tr_single+0x180/0x210 check_critical_timing+0x2b4/0x2c8 tracer_hardirqs_on+0x1c0/0x200 trace_hardirqs_on+0xec/0x378 el0_svc_common+0x64/0x260 do_el0_svc+0x90/0xf8 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb8 el0_sync+0x180/0x1c0 //<---- /* wait for all the updates to complete */ for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu]; //4. get cpu_buffer, cpu_buffer(B) is used in the following process, //the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong. //for example, cpu_buffer(A)->update_done will leave be set 1, and will //not 'wait_for_completion' at the next resize round. if (!cpu_buffer->nr_pages_to_update) continue; if (cpu_online(cpu)) wait_for_completion(&cpu_buffer->update_done); cpu_buffer->nr_pages_to_update = 0; } ... } //5. the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong, //Continuing to run in the wrong state, then oops occurs. Link: https://lore.kernel.org/linux-trace-kernel/202307191558478409990@zte.com.cn Signed-off-by: Chen Lin <chen.lin5@zte.com.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-13tracing: Fix memory leak of iter->temp when reading trace_pipeZheng Yejian1-0/+1
kmemleak reports: unreferenced object 0xffff88814d14e200 (size 256): comm "cat", pid 336, jiffies 4294871818 (age 779.490s) hex dump (first 32 bytes): 04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................ 0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z...... backtrace: [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140 [<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0 [<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0 [<ffffffff9bc94490>] print_trace_line+0x3e0/0x950 [<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0 [<ffffffff9bf03a43>] vfs_read+0x143/0x520 [<ffffffff9bf04c2d>] ksys_read+0xbd/0x160 [<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90 [<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 when reading file 'trace_pipe', 'iter->temp' is allocated or relocated in trace_find_next_entry() but not freed before 'trace_pipe' is closed. To fix it, free 'iter->temp' in tracing_release_pipe(). Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: ff895103a84ab ("tracing: Save off entry when peeking at next entry") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-12tracing: Stop FORTIFY_SOURCE complaining about stack trace callerSteven Rostedt (Google)1-2/+19
The stack_trace event is an event created by the tracing subsystem to store stack traces. It originally just contained a hard coded array of 8 words to hold the stack, and a "size" to know how many entries are there. This is exported to user space as: name: kernel_stack ID: 4 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:int size; offset:8; size:4; signed:1; field:unsigned long caller[8]; offset:16; size:64; signed:0; print fmt: "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n",i (void *)REC->caller[0], (void *)REC->caller[1], (void *)REC->caller[2], (void *)REC->caller[3], (void *)REC->caller[4], (void *)REC->caller[5], (void *)REC->caller[6], (void *)REC->caller[7] Where the user space tracers could parse the stack. The library was updated for this specific event to only look at the size, and not the array. But some older users still look at the array (note, the older code still checks to make sure the array fits inside the event that it read. That is, if only 4 words were saved, the parser would not read the fifth word because it will see that it was outside of the event size). This event was changed a while ago to be more dynamic, and would save a full stack even if it was greater than 8 words. It does this by simply allocating more ring buffer to hold the extra words. Then it copies in the stack via: memcpy(&entry->caller, fstack->calls, size); As the entry is struct stack_entry, that is created by a macro to both create the structure and export this to user space, it still had the caller field of entry defined as: unsigned long caller[8]. When the stack is greater than 8, the FORTIFY_SOURCE code notices that the amount being copied is greater than the source array and complains about it. It has no idea that the source is pointing to the ring buffer with the required allocation. To hide this from the FORTIFY_SOURCE logic, pointer arithmetic is used: ptr = ring_buffer_event_data(event); entry = ptr; ptr += offsetof(typeof(*entry), caller); memcpy(ptr, fstack->calls, size); Link: https://lore.kernel.org/all/20230612160748.4082850-1-svens@linux.ibm.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Reported-by: Sven Schnelle <svens@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-06Merge tag 'trace-v6.5-2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix bad git merge of #endif in arm64 code A merge of the arm64 tree caused #endif to go into the wrong place - Fix crash on lseek of write access to tracefs/error_log Opening error_log as write only, and then doing an lseek() causes a kernel panic, because the lseek() handle expects a "seq_file" to exist (which is not done on write only opens). Use tracing_lseek() that tests for this instead of calling the default seq lseek handler. - Check for negative instead of -E2BIG for error on strscpy() returns Instead of testing for -E2BIG from strscpy(), to be more robust, check for less than zero, which will make sure it catches any error that strscpy() may someday return. * tag 'trace-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/boot: Test strscpy() against less than zero for error arm64: ftrace: fix build error with CONFIG_FUNCTION_GRAPH_TRACER=n tracing: Fix null pointer dereference in tracing_err_log_open()
2023-07-05tracing: Fix null pointer dereference in tracing_err_log_open()Mateusz Stachyra1-1/+1
Fix an issue in function 'tracing_err_log_open'. The function doesn't call 'seq_open' if the file is opened only with write permissions, which results in 'file->private_data' being left as null. If we then use 'lseek' on that opened file, 'seq_lseek' dereferences 'file->private_data' in 'mutex_lock(&m->lock)', resulting in a kernel panic. Writing to this node requires root privileges, therefore this bug has very little security impact. Tracefs node: /sys/kernel/tracing/error_log Example Kernel panic: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Call trace: mutex_lock+0x30/0x110 seq_lseek+0x34/0xb8 __arm64_sys_lseek+0x6c/0xb8 invoke_syscall+0x58/0x13c el0_svc_common+0xc4/0x10c do_el0_svc+0x24/0x98 el0_svc+0x24/0x88 el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x1b4/0x1b8 Code: d503201f aa0803e0 aa1f03e1 aa0103e9 (c8e97d02) ---[ end trace 561d1b49c12cf8a5 ]--- Kernel panic - not syncing: Oops: Fatal exception Link: https://lore.kernel.org/linux-trace-kernel/20230703155237eucms1p4dfb6a19caa14c79eb6c823d127b39024@eucms1p4 Link: https://lore.kernel.org/linux-trace-kernel/20230704102706eucms1p30d7ecdcc287f46ad67679fc8491b2e0f@eucms1p3 Cc: stable@vger.kernel.org Fixes: 8a062902be725 ("tracing: Add tracing error log") Signed-off-by: Mateusz Stachyra <m.stachyra@samsung.com> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-30Merge tag 'probes-v6.5' of ↵Linus Torvalds1-1/+12
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull probes updates from Masami Hiramatsu: - fprobe: Pass return address to the fprobe entry/exit callbacks so that the callbacks don't need to analyze pt_regs/stack to find the function return address. - kprobe events: cleanup usage of TPARG_FL_FENTRY and TPARG_FL_RETURN flags so that those are not set at once. - fprobe events: - Add a new fprobe events for tracing arbitrary function entry and exit as a trace event. - Add a new tracepoint events for tracing raw tracepoint as a trace event. This allows user to trace non user-exposed tracepoints. - Move eprobe's event parser code into probe event common file. - Introduce BTF (BPF type format) support to kernel probe (kprobe, fprobe and tracepoint probe) events so that user can specify traced function arguments by name. This also applies the type of argument when fetching the argument. - Introduce '$arg*' wildcard support if BTF is available. This expands the '$arg*' meta argument to all function argument automatically. - Check the return value types by BTF. If the function returns 'void', '$retval' is rejected. - Add some selftest script for fprobe events, tracepoint events and BTF support. - Update documentation about the fprobe events. - Some fixes for above features, document and selftests. - selftests for ftrace (in addition to the new fprobe events): - Add a test case for multiple consecutive probes in a function which checks if ftrace based kprobe, optimized kprobe and normal kprobe can be defined in the same target function. - Add a test case for optimized probe, which checks whether kprobe can be optimized or not. * tag 'probes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/probes: Fix tracepoint event with $arg* to fetch correct argument Documentation: Fix typo of reference file name tracing/probes: Fix to return NULL and keep using current argc selftests/ftrace: Add new test case which checks for optimized probes selftests/ftrace: Add new test case which adds multiple consecutive probes in a function Documentation: tracing/probes: Add fprobe event tracing document selftests/ftrace: Add BTF arguments test cases selftests/ftrace: Add tracepoint probe test case tracing/probes: Add BTF retval type support tracing/probes: Add $arg* meta argument for all function args tracing/probes: Support function parameters if BTF is available tracing/probes: Move event parameter fetching code to common parser tracing/probes: Add tracepoint support on fprobe_events selftests/ftrace: Add fprobe related testcases tracing/probes: Add fprobe events for tracing function entry and exit. tracing/probes: Avoid setting TPARG_FL_FENTRY and TPARG_FL_RETURN fprobe: Pass return address to the handlers
2023-06-27Merge tag 'hardening-v6.5-rc1' of ↵Linus Torvalds1-4/+4
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: "There are three areas of note: A bunch of strlcpy()->strscpy() conversions ended up living in my tree since they were either Acked by maintainers for me to carry, or got ignored for multiple weeks (and were trivial changes). The compiler option '-fstrict-flex-arrays=3' has been enabled globally, and has been in -next for the entire devel cycle. This changes compiler diagnostics (though mainly just -Warray-bounds which is disabled) and potential UBSAN_BOUNDS and FORTIFY _warning_ coverage. In other words, there are no new restrictions, just potentially new warnings. Any new FORTIFY warnings we've seen have been fixed (usually in their respective subsystem trees). For more details, see commit df8fc4e934c12b. The under-development compiler attribute __counted_by has been added so that we can start annotating flexible array members with their associated structure member that tracks the count of flexible array elements at run-time. It is possible (likely?) that the exact syntax of the attribute will change before it is finalized, but GCC and Clang are working together to sort it out. Any changes can be made to the macro while we continue to add annotations. As an example of that last case, I have a treewide commit waiting with such annotations found via Coccinelle: https://git.kernel.org/linus/adc5b3cb48a049563dc673f348eab7b6beba8a9b Also see commit dd06e72e68bcb4 for more details. Summary: - Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko) - Convert strreplace() to return string start (Andy Shevchenko) - Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook) - Add missing function prototypes seen with W=1 (Arnd Bergmann) - Fix strscpy() kerndoc typo (Arne Welzel) - Replace strlcpy() with strscpy() across many subsystems which were either Acked by respective maintainers or were trivial changes that went ignored for multiple weeks (Azeem Shaikh) - Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers) - Add KUnit tests for strcat()-family - Enable KUnit tests of FORTIFY wrappers under UML - Add more complete FORTIFY protections for strlcat() - Add missed disabling of FORTIFY for all arch purgatories. - Enable -fstrict-flex-arrays=3 globally - Tightening UBSAN_BOUNDS when using GCC - Improve checkpatch to check for strcpy, strncpy, and fake flex arrays - Improve use of const variables in FORTIFY - Add requested struct_size_t() helper for types not pointers - Add __counted_by macro for annotating flexible array size members" * tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (54 commits) netfilter: ipset: Replace strlcpy with strscpy uml: Replace strlcpy with strscpy um: Use HOST_DIR for mr