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2025-10-11Merge tag 'trace-v6.18-3' of ↵Linus Torvalds1-4/+8
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: "The previous fix to trace_marker required updating trace_marker_raw as well. The difference between trace_marker_raw from trace_marker is that the raw version is for applications to write binary structures directly into the ring buffer instead of writing ASCII strings. This is for applications that will read the raw data from the ring buffer and get the data structures directly. It's a bit quicker than using the ASCII version. Unfortunately, it appears that our test suite has several tests that test writes to the trace_marker file, but lacks any tests to the trace_marker_raw file (this needs to be remedied). Two issues came about the update to the trace_marker_raw file that syzbot found: - Fix tracing_mark_raw_write() to use per CPU buffer The fix to use the per CPU buffer to copy from user space was needed for both the trace_maker and trace_maker_raw file. The fix for reading from user space into per CPU buffers properly fixed the trace_marker write function, but the trace_marker_raw file wasn't fixed properly. The user space data was correctly written into the per CPU buffer, but the code that wrote into the ring buffer still used the user space pointer and not the per CPU buffer that had the user space data already written. - Stop the fortify string warning from writing into trace_marker_raw After converting the copy_from_user_nofault() into a memcpy(), another issue appeared. As writes to the trace_marker_raw expects binary data, the first entry is a 4 byte identifier. The entry structure is defined as: struct { struct trace_entry ent; int id; char buf[]; }; The size of this structure is reserved on the ring buffer with: size = sizeof(*entry) + cnt; Then it is copied from the buffer into the ring buffer with: memcpy(&entry->id, buf, cnt); This use to be a copy_from_user_nofault(), but now converting it to a memcpy() triggers the fortify-string code, and causes a warning. The allocated space is actually more than what is copied, as the cnt used also includes the entry->id portion. Allocating sizeof(*entry) plus cnt is actually allocating 4 bytes more than what is needed. Change the size function to: size = struct_size(entry, buf, cnt - sizeof(entry->id)); And update the memcpy() to unsafe_memcpy()" * tag 'trace-v6.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Stop fortify-string from warning in tracing_mark_raw_write() tracing: Fix tracing_mark_raw_write() to use buf and not ubuf
2025-10-11tracing: Stop fortify-string from warning in tracing_mark_raw_write()Steven Rostedt1-2/+6
The way tracing_mark_raw_write() records its data is that it has the following structure: struct { struct trace_entry; int id; char buf[]; }; But memcpy(&entry->id, buf, size) triggers the following warning when the size is greater than the id: ------------[ cut here ]------------ memcpy: detected field-spanning write (size 6) of single field "&entry->id" at kernel/trace/trace.c:7458 (size 4) WARNING: CPU: 7 PID: 995 at kernel/trace/trace.c:7458 write_raw_marker_to_buffer.isra.0+0x1f9/0x2e0 Modules linked in: CPU: 7 UID: 0 PID: 995 Comm: bash Not tainted 6.17.0-test-00007-g60b82183e78a-dirty #211 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 RIP: 0010:write_raw_marker_to_buffer.isra.0+0x1f9/0x2e0 Code: 04 00 75 a7 b9 04 00 00 00 48 89 de 48 89 04 24 48 c7 c2 e0 b1 d1 b2 48 c7 c7 40 b2 d1 b2 c6 05 2d 88 6a 04 01 e8 f7 e8 bd ff <0f> 0b 48 8b 04 24 e9 76 ff ff ff 49 8d 7c 24 04 49 8d 5c 24 08 48 RSP: 0018:ffff888104c3fc78 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 1ffffffff6b363b4 RDI: 0000000000000001 RBP: ffff888100058a00 R08: ffffffffb041d459 R09: ffffed1020987f40 R10: 0000000000000007 R11: 0000000000000001 R12: ffff888100bb9010 R13: 0000000000000000 R14: 00000000000003e3 R15: ffff888134800000 FS: 00007fa61d286740(0000) GS:ffff888286cad000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560d28d509f1 CR3: 00000001047a4006 CR4: 0000000000172ef0 Call Trace: <TASK> tracing_mark_raw_write+0x1fe/0x290 ? __pfx_tracing_mark_raw_write+0x10/0x10 ? security_file_permission+0x50/0xf0 ? rw_verify_area+0x6f/0x4b0 vfs_write+0x1d8/0xdd0 ? __pfx_vfs_write+0x10/0x10 ? __pfx_css_rstat_updated+0x10/0x10 ? count_memcg_events+0xd9/0x410 ? fdget_pos+0x53/0x5e0 ksys_write+0x182/0x200 ? __pfx_ksys_write+0x10/0x10 ? do_user_addr_fault+0x4af/0xa30 do_syscall_64+0x63/0x350 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fa61d318687 Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffd87fe0120 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fa61d286740 RCX: 00007fa61d318687 RDX: 0000000000000006 RSI: 0000560d28d509f0 RDI: 0000000000000001 RBP: 0000560d28d509f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000006 R13: 00007fa61d4715c0 R14: 00007fa61d46ee80 R15: 0000000000000000 </TASK> ---[ end trace 0000000000000000 ]--- This is because fortify string sees that the size of entry->id is only 4 bytes, but it is writing more than that. But this is OK as the dynamic_array is allocated to handle that copy. The size allocated on the ring buffer was actually a bit too big: size = sizeof(*entry) + cnt; But cnt includes the 'id' and the buffer data, so adding cnt to the size of *entry actually allocates too much on the ring buffer. Change the allocation to: size = struct_size(entry, buf, cnt - sizeof(entry->id)); and the memcpy() to unsafe_memcpy() with an added justification. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20251011112032.77be18e4@gandalf.local.home Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space") Reported-by: syzbot+9a2ede1643175f350105@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68e973f5.050a0220.1186a4.0010.GAE@google.com/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-10-10tracing: Fix tracing_mark_raw_write() to use buf and not ubufSteven Rostedt1-2/+2
The fix to use a per CPU buffer to read user space tested only the writes to trace_marker. But it appears that the selftests are missing tests to the trace_maker_raw file. The trace_maker_raw file is used by applications that writes data structures and not strings into the file, and the tools read the raw ring buffer to process the structures it writes. The fix that reads the per CPU buffers passes the new per CPU buffer to the trace_marker file writes, but the update to the trace_marker_raw write read the data from user space into the per CPU buffer, but then still used then passed the user space address to the function that records the data. Pass in the per CPU buffer and not the user space address. TODO: Add a test to better test trace_marker_raw. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20251011035243.386098147@kernel.org Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space") Reported-by: syzbot+9a2ede1643175f350105@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68e973f5.050a0220.1186a4.0010.GAE@google.com/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-10-09Merge tag 'trace-v6.18-2' of ↵Linus Torvalds1-48/+220
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing clean up and fixes from Steven Rostedt: - Have osnoise tracer use memdup_user_nul() The function osnoise_cpus_write() open codes a kmalloc() and then a copy_from_user() and then adds a nul byte at the end which is the same as simply using memdup_user_nul(). - Fix wakeup and irq tracers when failing to acquire calltime When the wakeup and irq tracers use the function graph tracer for tracing function times, it saves a timestamp into the fgraph shadow stack. It is possible that this could fail to be stored. If that happens, it exits the routine early. These functions also disable nesting of the operations by incremeting the data "disable" counter. But if the calltime exits out early, it never increments the counter back to what it needs to be. Since there's only a couple of lines of code that does work after acquiring the calltime, instead of exiting out early, reverse the if statement to be true if calltime is acquired, and place the code that is to be done within that if block. The clean up will always be done after that. - Fix ring_buffer_map() return value on failure of __rb_map_vma() If __rb_map_vma() fails in ring_buffer_map(), it does not return an error. This means the caller will be working against a bad vma mapping. Have ring_buffer_map() return an error when __rb_map_vma() fails. - Fix regression of writing to the trace_marker file A bug fix was made to change __copy_from_user_inatomic() to copy_from_user_nofault() in the trace_marker write function. The trace_marker file is used by applications to write into it (usually with a file descriptor opened at the start of the program) to record into the tracing system. It's usually used in critical sections so the write to trace_marker is highly optimized. The reason for copying in an atomic section is that the write reserves space on the ring buffer and then writes directly into it. After it writes, it commits the event. The time between reserve and commit must have preemption disabled. The trace marker write does not have any locking nor can it allocate due to the nature of it being a critical path. Unfortunately, converting __copy_from_user_inatomic() to copy_from_user_nofault() caused a regression in Android. Now all the writes from its applications trigger the fault that is rejected by the _nofault() version that wasn't rejected by the _inatomic() version. Instead of getting data, it now just gets a trace buffer filled with: tracing_mark_write: <faulted> To fix this, on opening of the trace_marker file, allocate per CPU buffers that can be used by the write call. Then when entering the write call, do the following: preempt_disable(); cpu = smp_processor_id(); buffer = per_cpu_ptr(cpu_buffers, cpu); do { cnt = nr_context_switches_cpu(cpu); migrate_disable(); preempt_enable(); ret = copy_from_user(buffer, ptr, size); preempt_disable(); migrate_enable(); } while (!ret && cnt != nr_context_switches_cpu(cpu)); if (!ret) ring_buffer_write(buffer); preempt_enable(); This works similarly to seqcount. As it must enabled preemption to do a copy_from_user() into a per CPU buffer, if it gets preempted, the buffer could be corrupted by another task. To handle this, read the number of context switches of the current CPU, disable migration, enable preemption, copy the data from user space, then immediately disable preemption again. If the number of context switches is the same, the buffer is still valid. Otherwise it must be assumed that the buffer may have been corrupted and it needs to try again. Now the trace_marker write can get the user data even if it has to fault it in, and still not grab any locks of its own. * tag 'trace-v6.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Have trace_marker use per-cpu data to read user space ring buffer: Propagate __rb_map_vma return value to caller tracing: Fix irqoff tracers on failure of acquiring calltime tracing: Fix wakeup tracers on failure of acquiring calltime tracing/osnoise: Replace kmalloc + copy_from_user with memdup_user_nul
2025-10-08tracing: Have trace_marker use per-cpu data to read user spaceSteven Rostedt1-48/+220
It was reported that using __copy_from_user_inatomic() can actually schedule. Which is bad when preemption is disabled. Even though there's logic to check in_atomic() is set, but this is a nop when the kernel is configured with PREEMPT_NONE. This is due to page faulting and the code could schedule with preemption disabled. Link: https://lore.kernel.org/all/20250819105152.2766363-1-luogengkun@huaweicloud.com/ The solution was to change the __copy_from_user_inatomic() to copy_from_user_nofault(). But then it was reported that this caused a regression in Android. There's several applications writing into trace_marker() in Android, but now instead of showing the expected data, it is showing: tracing_mark_write: <faulted> After reverting the conversion to copy_from_user_nofault(), Android was able to get the data again. Writes to the trace_marker is a way to efficiently and quickly enter data into the Linux tracing buffer. It takes no locks and was designed to be as non-intrusive as possible. This means it cannot allocate memory, and must use pre-allocated data. A method that is actively being worked on to have faultable system call tracepoints read user space data is to allocate per CPU buffers, and use them in the callback. The method uses a technique similar to seqcount. That is something like this: preempt_disable(); cpu = smp_processor_id(); buffer = this_cpu_ptr(&pre_allocated_cpu_buffers, cpu); do { cnt = nr_context_switches_cpu(cpu); migrate_disable(); preempt_enable(); ret = copy_from_user(buffer, ptr, size); preempt_disable(); migrate_enable(); } while (!ret && cnt != nr_context_switches_cpu(cpu)); if (!ret) ring_buffer_write(buffer); preempt_enable(); It's a little more involved than that, but the above is the basic logic. The idea is to acquire the current CPU buffer, disable migration, and then enable preemption. At this moment, it can safely use copy_from_user(). After reading the data from user space, it disables preemption again. It then checks to see if there was any new scheduling on this CPU. If there was, it must assume that the buffer was corrupted by another task. If there wasn't, then the buffer is still valid as only tasks in preemptable context can write to this buffer and only those that are running on the CPU. By using this method, where trace_marker open allocates the per CPU buffers, trace_marker writes can access user space and even fault it in, without having to allocate or take any locks of its own. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Luo Gengkun <luogengkun@huaweicloud.com> Cc: Wattson CI <wattson-external@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/20251008124510.6dba541a@gandalf.local.home Fixes: 3d62ab32df065 ("tracing: Fix tracing_marker may trigger page fault during preempt_disable") Reported-by: Runping Lai <runpinglai@google.com> Tested-by: Runping Lai <runpinglai@google.com> Closes: https://lore.kernel.org/linux-trace-kernel/20251007003417.3470979-2-runpinglai@google.com/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-10-03Merge tag 'pull-fs_context' of ↵Linus Torvalds1-2/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull fs_context updates from Al Viro: "Change vfs_parse_fs_string() calling conventions Get rid of the length argument (almost all callers pass strlen() of the string argument there), add vfs_parse_fs_qstr() for the cases that do want separate length" * tag 'pull-fs_context' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: do_nfs4_mount(): switch to vfs_parse_fs_string() change the calling conventions for vfs_parse_fs_string()
2025-09-08tracing: Silence warning when chunk allocation fails in trace_pid_writePu Lehui1-1/+5
Syzkaller trigger a fault injection warning: WARNING: CPU: 1 PID: 12326 at tracepoint_add_func+0xbfc/0xeb0 Modules linked in: CPU: 1 UID: 0 PID: 12326 Comm: syz.6.10325 Tainted: G U 6.14.0-rc5-syzkaller #0 Tainted: [U]=USER Hardware name: Google Compute Engine/Google Compute Engine RIP: 0010:tracepoint_add_func+0xbfc/0xeb0 kernel/tracepoint.c:294 Code: 09 fe ff 90 0f 0b 90 0f b6 74 24 43 31 ff 41 bc ea ff ff ff RSP: 0018:ffffc9000414fb48 EFLAGS: 00010283 RAX: 00000000000012a1 RBX: ffffffff8e240ae0 RCX: ffffc90014b78000 RDX: 0000000000080000 RSI: ffffffff81bbd78b RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffffffffef R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff81c264f0 FS: 00007f27217f66c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e80dff8 CR3: 00000000268f8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> tracepoint_probe_register_prio+0xc0/0x110 kernel/tracepoint.c:464 register_trace_prio_sched_switch include/trace/events/sched.h:222 [inline] register_pid_events kernel/trace/trace_events.c:2354 [inline] event_pid_write.isra.0+0x439/0x7a0 kernel/trace/trace_events.c:2425 vfs_write+0x24c/0x1150 fs/read_write.c:677 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f We can reproduce the warning by following the steps below: 1. echo 8 >> set_event_notrace_pid. Let tr->filtered_pids owns one pid and register sched_switch tracepoint. 2. echo ' ' >> set_event_pid, and perform fault injection during chunk allocation of trace_pid_list_alloc. Let pid_list with no pid and assign to tr->filtered_pids. 3. echo ' ' >> set_event_pid. Let pid_list is NULL and assign to tr->filtered_pids. 4. echo 9 >> set_event_pid, will trigger the double register sched_switch tracepoint warning. The reason is that syzkaller injects a fault into the chunk allocation in trace_pid_list_alloc, causing a failure in trace_pid_list_set, which may trigger double register of the same tracepoint. This only occurs when the system is about to crash, but to suppress this warning, let's add failure handling logic to trace_pid_list_set. Link: https://lore.kernel.org/20250908024658.2390398-1-pulehui@huaweicloud.com Fixes: 8d6e90983ade ("tracing: Create a sparse bitmask for pid filtering") Reported-by: syzbot+161412ccaeff20ce4dde@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67cb890e.050a0220.d8275.022e.GAE@google.com Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-04change the calling conventions for vfs_parse_fs_string()Al Viro1-2/+1
Absolute majority of callers are passing the 4th argument equal to strlen() of the 3rd one. Drop the v_size argument, add vfs_parse_fs_qstr() for the cases that want independent length. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-09-02tracing: Fix tracing_marker may trigger page fault during preempt_disableLuo Gengkun1-2/+2
Both tracing_mark_write and tracing_mark_raw_write call __copy_from_user_inatomic during preempt_disable. But in some case, __copy_from_user_inatomic may trigger page fault, and will call schedule() subtly. And if a task is migrated to other cpu, the following warning will be trigger: if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))) An example can illustrate this issue: process flow CPU --------------------------------------------------------------------- tracing_mark_raw_write(): cpu:0 ... ring_buffer_lock_reserve(): cpu:0 ... cpu = raw_smp_processor_id() cpu:0 cpu_buffer = buffer->buffers[cpu] cpu:0 ... ... __copy_from_user_inatomic(): cpu:0 ... # page fault do_mem_abort(): cpu:0 ... # Call schedule schedule() cpu:0 ... # the task schedule to cpu1 __buffer_unlock_commit(): cpu:1 ... ring_buffer_unlock_commit(): cpu:1 ... cpu = raw_smp_processor_id() cpu:1 cpu_buffer = buffer->buffers[cpu] cpu:1 As shown above, the process will acquire cpuid twice and the return values are not the same. To fix this problem using copy_from_user_nofault instead of __copy_from_user_inatomic, as the former performs 'access_ok' before copying. Link: https://lore.kernel.org/20250819105152.2766363-1-luogengkun@huaweicloud.com Fixes: 656c7f0d2d2b ("tracing: Replace kmap with copy_from_user() in trace_marker writing") Signed-off-by: Luo Gengkun <luogengkun@huaweicloud.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-22ftrace: Fix potential warning in trace_printk_seq during ftrace_dumpTengda Wu1-2/+2
When calling ftrace_dump_one() concurrently with reading trace_pipe, a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race condition. The issue occurs because: CPU0 (ftrace_dump) CPU1 (reader) echo z > /proc/sysrq-trigger !trace_empty(&iter) trace_iterator_reset(&iter) <- len = size = 0 cat /sys/kernel/tracing/trace_pipe trace_find_next_entry_inc(&iter) __find_next_entry ring_buffer_empty_cpu <- all empty return NULL trace_printk_seq(&iter.seq) WARN_ON_ONCE(s->seq.len >= s->seq.size) In the context between trace_empty() and trace_find_next_entry_inc() during ftrace_dump, the ring buffer data was consumed by other readers. This caused trace_find_next_entry_inc to return NULL, failing to populate `iter.seq`. At this point, due to the prior trace_iterator_reset, both `iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal, the WARN_ON_ONCE condition is triggered. Move the trace_printk_seq() into the if block that checks to make sure the return value of trace_find_next_entry_inc() is non-NULL in ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before subsequent operations. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Ingo Molnar <mingo@elte.hu> Link: https://lore.kernel.org/20250822033343.3000289-1-wutengda@huaweicloud.com Fixes: d769041f8653 ("ring_buffer: implement new locking") Signed-off-by: Tengda Wu <wutengda@huaweicloud.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-20tracing: Limit access to parser->buffer when trace_get_user failedPu Lehui1-6/+12
When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered: BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165 CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0 __asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618 __fput+0x364/0xa58 ____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0 The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0. Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250813040232.1344527-1-pulehui@huaweicloud.com Fixes: 8c9af478c06b ("ftrace: Handle commands when closing set_ftrace_filter file") Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-03Merge tag 'trace-v6.17-2' of ↵Linus Torvalds1-185/+102
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull more tracing updates from Steven Rostedt: - Remove unneeded goto out statements Over time, the logic was restructured but left a "goto out" where the out label simply did a "return ret;". Instead of jumping to this out label, simply return immediately and remove the out label. - Add guard(ring_buffer_nest) Some calls to the tracing ring buffer can happen when the ring buffer is already being written to at the same context (for example, a trace_printk() in between a ring_buffer_lock_reserve() and a ring_buffer_unlock_commit()). In order to not trigger the recursion detection, these functions use ring_buffer_nest_start() and ring_buffer_nest_end(). Create a guard() for these functions so that their use cases can be simplified and not need to use goto for the release. - Clean up the tracing code with guard() and __free() logic There were several locations that were prime candidates for using guard() and __free() helpers. Switch them over to use them. - Fix output of function argument traces for unsigned int values The function tracer with "func-args" option set will record up to 6 argument registers and then use BTF to format them for human consumption when the trace file is read. There are several arguments that are "unsigned long" and even "unsigned int" that are either and address or a mask. It is easier to understand if they were printed using hexadecimal instead of decimal. The old method just printed all non-pointer values as signed integers, which made it even worse for unsigned integers. For instance, instead of: __local_bh_disable_ip(ip=-2127311112, cnt=256) <-handle_softirqs show: __local_bh_disable_ip(ip=0xffffffff8133cef8, cnt=0x100) <-handle_softirqs" * tag 'trace-v6.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Have unsigned int function args displayed as hexadecimal ring-buffer: Convert ring_buffer_write() to use guard(preempt_notrace) tracing: Use __free(kfree) in trace.c to remove gotos tracing: Add guard() around locks and mutexes in trace.c tracing: Add guard(ring_buffer_nest) tracing: Remove unneeded goto out logic
2025-08-03Merge tag 'modules-6.17-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux Pull module updates from Daniel Gomez: "This is a small set of changes for modules, primarily to extend module users to use the module data structures in combination with the already no-op stub module functions, even when support for modules is disabled in the kernel configuration. This change follows the kernel's coding style for conditional compilation and allows kunit code to drop all CONFIG_MODULES ifdefs, which is also part of the changes. This should allow others part of the kernel to do the same cleanup. The remaining changes include a fix for module name length handling which could potentially lead to the removal of an incorrect module, and various cleanups" * tag 'modules-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux: module: Rename MAX_PARAM_PREFIX_LEN to __MODULE_NAME_LEN tracing: Replace MAX_PARAM_PREFIX_LEN with MODULE_NAME_LEN module: Restore the moduleparam prefix length check module: Remove unnecessary +1 from last_unloaded_module::name size module: Prevent silent truncation of module name in delete_module(2) kunit: test: Drop CONFIG_MODULE ifdeffery module: make structure definitions always visible module: move 'struct module_use' to internal.h
2025-08-01tracing: Use __free(kfree) in trace.c to remove gotosSteven Rostedt1-24/+12
There's a couple of locations that have goto out in trace.c for the only purpose of freeing a variable that was allocated. These can be replaced with __free(kfree). Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20250801203858.040892777@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-01tracing: Add guard() around locks and mutexes in trace.cSteven Rostedt1-98/+46
There's several locations in trace.c that can be simplified by using guards around raw_spin_lock_irqsave, mutexes and preempt disabling. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20250801203857.879085376@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-01tracing: Add guard(ring_buffer_nest)Steven Rostedt1-40/+29
Some calls to the tracing ring buffer can happen when the ring buffer is already being written to by the same context (for example, a trace_printk() in between a ring_buffer_lock_reserve() and a ring_buffer_unlock_commit()). In order to not trigger the recursion detection, these functions use ring_buffer_nest_start() and ring_buffer_nest_end(). Create a guard() for these functions so that their use cases can be simplified and not need to use goto for the release. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20250801203857.710501021@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-01tracing: Remove unneeded goto out logicSteven Rostedt1-23/+15
Several places in the trace.c file there's a goto out where the out is simply a return. There's no reason to jump to the out label if it's not doing any more logic but simply returning from the function. Replace the goto outs with a return and remove the out labels. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/20250801203857.538726745@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-01Merge tag 'trace-v6.17' of ↵Linus Torvalds1-21/+28
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - Deprecate auto-mounting tracefs to /sys/kernel/debug/tracing When tracefs was first introduced back in 2014, the directory /sys/kernel/tracing was added and is the designated location to mount tracefs. To keep backward compatibility, tracefs was auto-mounted in /sys/kernel/debug/tracing as well. All distros now mount tracefs on /sys/kernel/tracing. Having it seen in two different locations has lead to various issues and inconsistencies. The VFS folks have to also maintain debugfs_create_automount() for this single user. It's been over 10 years. Tooling and scripts should start replacing the debugfs location with the tracefs one. The reason tracefs was created in the first place was to allow access to the tracing facilities without the need to configure debugfs into the kernel. Using tracefs should now be more robust. A new config is created: CONFIG_TRACEFS_AUTOMOUNT_DEPRECATED which is default y, so that the kernel is still built with the automount. This config allows those that want to remove the automount from debugfs to do so. When tracefs is accessed from /sys/kernel/debug/tracing, the following printk is triggerd: pr_warn("NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030\n"); This gives users another 5 years to fix their scripts. - Use queue_rcu_work() instead of call_rcu() for freeing event filters The number of filters to be free can be many depending on the number of events within an event system. Freeing them from softirq context can potentially cause undesired latency. Use the RCU workqueue to free them instead. - Remove pointless memory barriers in latency code Memory barriers were added to some of the latency code a long time ago with the idea of "making them visible", but that's not what memory barriers are for. They are to synchronize access between different variables. There was no synchronization here making them pointless. - Remove "__attribute__()" from the type field of event format When LLVM is used to compile the kernel with CONFIG_DEBUG_INFO_BTF=y and PAHOLE_HAS_BTF_TAG=y, some of the format fields get expanded with the following: field:const char * filename; offset:24; size:8; signed:0; Turns into: field:const char __attribute__((btf_type_tag("user"))) * filename; offset:24; size:8; signed:0; This confuses parsers. Add code to strip these tags from the strings. - Add eprobe config option CONFIG_EPROBE_EVENTS Eprobes were added back in 5.15 but were only enabled when another probe was enabled (kprobe, fprobe, uprobe, etc). The eprobes had no config option of their own. Add one as they should be a separate entity. It's default y to keep with the old kernels but still has dependencies on TRACING and HAVE_REGS_AND_STACK_ACCESS_API. - Add eprobe documentation When eprobes were added back in 5.15 no documentation was added to describe them. This needs to be rectified. - Replace open coded cpumask_next_wrap() in move_to_next_cpu() - Have preemptirq_delay_run() use off-stack CPU mask - Remove obsolete comment about pelt_cfs event DECLARE_TRACE() appends "_tp" to trace events now, but the comment above pelt_cfs still mentioned appending it manually. - Remove EVENT_FILE_FL_SOFT_MODE flag The SOFT_MODE flag was required when the soft enabling and disabling of trace events was first introduced. But there was a bug with this approach as it only worked for a single instance. When multiple users required soft disabling and disabling the code was changed to have a ref count. The SOFT_MODE flag is now set iff the ref count is non zero. This is redundant and just reading the ref count is good enough. - Fix typo in comment * tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: Documentation: tracing: Add documentation about eprobes tracing: Have eprobes have their own config option tracing: Remove "__attribute__()" from the type field of event format tracing: Deprecate auto-mounting tracefs in debugfs tracing: Fix comment in trace_module_remove_events() tracing: Remove EVENT_FILE_FL_SOFT_MODE flag tracing: Remove pointless memory barriers tracing/sched: Remove obsolete comment on suffixes kernel: trace: preemptirq_delay_test: use offstack cpu mask tracing: Use queue_rcu_work() to free filters tracing: Replace opencoded cpumask_next_wrap() in move_to_next_cpu()
2025-07-31tracing: Replace MAX_PARAM_PREFIX_LEN with MODULE_NAME_LENPetr Pavlu1-1/+1
Use the MODULE_NAME_LEN definition in module_exists() to obtain the maximum size of a module name, instead of using MAX_PARAM_PREFIX_LEN. The values are the same but MODULE_NAME_LEN is more appropriate in this context. MAX_PARAM_PREFIX_LEN was added in commit 730b69d22525 ("module: check kernel param length at compile time, not runtime") only to break a circular dependency between module.h and moduleparam.h, and should mostly be limited to use in moduleparam.h. Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Daniel Gomez <da.gomez@samsung.com> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20250630143535.267745-5-petr.pavlu@suse.com Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
2025-07-29tracing: Remove "__attribute__()" from the type field of event formatMasami Hiramatsu (Google)1-10/+18
With CONFIG_DEBUG_INFO_BTF=y and PAHOLE_HAS_BTF_TAG=y, `__user` is converted to `__attribute__((btf_type_tag("user")))`. In this case, some syscall events have it for __user data, like below; /sys/kernel/tracing # cat events/syscalls/sys_enter_openat/format name: sys_enter_openat ID: 720 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 __syscall_nr; offset:8; size:4; signed:1; field:int dfd; offset:16; size:8; signed:0; field:const char __attribute__((btf_type_tag("user"))) * filename; offset:24; size:8; signed:0; field:int flags; offset:32; size:8; signed:0; field:umode_t mode; offset:40; size:8; signed:0; Then the trace event filter fails to set the string acceptable flag (FILTER_PTR_STRING) to the field and rejects setting string filter; # echo 'filename.ustring ~ "*ftracetest-dir.wbx24v*"' \ >> events/syscalls/sys_enter_openat/filter sh: write error: Invalid argument # cat error_log [ 723.743637] event filter parse error: error: Expecting numeric field Command: filename.ustring ~ "*ftracetest-dir.wbx24v*" Since this __attribute__ makes format parsing complicated and not needed, remove the __attribute__(.*) from the type string. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/175376583493.1688759.12333973498014733551.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-23tracing: Deprecate auto-mounting tracefs in debugfsSteven Rostedt1-4/+10
In January 2015, tracefs was created to allow access to the tracing infrastructure without needing to compile in debugfs. When tracefs is configured, the directory /sys/kernel/tracing will exist and tooling is expected to use that path to access the tracing infrastructure. To allow backward compatibility, when debugfs is mounted, it would automount tracefs in its "tracing" directory so that tooling that had hard coded /sys/kernel/debug/tracing would still work. It has been over 10 years since the new interface was introduced, and all tooling should now be using it. Start the process of deprecating the old path so that it doesn't need to be maintained anymore. A new config is added to allow distributions to disable automounting of tracefs on debugfs. If /sys/kernel/debug/tracing is accessed, a pr_warn() will trigger stating: "NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030" Expect to remove this feature in 5 years (2030). Cc: <linux-trace-users@vger.kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/20250722170806.40c068c6@gandalf.local.home Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-22tracing: Remove pointless memory barriersNam Cao1-7/+0
Memory barriers are useful to ensure memory accesses from one CPU appear in the original order as seen by other CPUs. Some smp_rmb() and smp_wmb() are used, but they are not ordering multiple memory accesses. Remove them. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250626151940.1756398-1-namcao@linutronix.de Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-22ring-buffer: Remove ring_buffer_read_prepare_sync()Steven Rostedt1-10/+4
When the ring buffer was first introduced, reading the non-consuming "trace" file required disabling the writing of the ring buffer. To make sure the writing was fully disabled before iterating the buffer with a non-consuming read, it would set the disable flag of the buffer and then call an RCU synchronization to make sure all the buffers were synchronized. The function ring_buffer_read_start() originally would initialize the iterator and call an RCU synchronization, but this was for each individual per CPU buffer where this would get called many times on a machine with many CPUs before the trace file could be read. The commit 72c9ddfd4c5bf ("ring-buffer: Make non-consuming read less expensive with lots of cpus.") separated ring_buffer_read_start into ring_buffer_read_prepare(), ring_buffer_read_sync() and then ring_buffer_read_start() to allow each of the per CPU buffers to be prepared, call the read_buffer_read_sync() once, and then the ring_buffer_read_start() for each of the CPUs which made things much faster. The commit 1039221cc278 ("ring-buffer: Do not disable recording when there is an iterator") removed the requirement of disabling the recording of the ring buffer in order to iterate it, but it did not remove the synchronization that was happening that was required to wait for all the buffers to have no more writers. It's now OK for the buffers to have writers and no synchronization is needed. Remove the synchronization and put back the interface for the ring buffer iterator back before commit 72c9ddfd4c5bf was applied. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20250630180440.3eabb514@batman.local.home Reported-by: David Howells <dhowells@redhat.com> Fixes: 1039221cc278 ("ring-buffer: Do not disable recording when there is an iterator") Tested-by: David Howells <dhowells@redhat.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-05-30Merge tag 'trace-ringbuffer-v6.16' of ↵Linus Torvalds1-4/+22
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ring-buffer updates from Steven Rostedt: - Allow the persistent ring buffer to be memory mapped In the last merge window there was issues with the implementation of mapping the persistent ring buffer because it was assumed that the persistent memory was just physical memory without being part of the kernel virtual address space. But this was incorrect and the persistent ring buffer can be mapped the same way as the allocated ring buffer is mapped. The metadata for the persistent ring buffer is different than the normal ring buffer and the organization of mapping it to user space is a little different. Make the updates needed to the meta data to allow the persistent ring buffer to be mapped to user space. - Fix cpus_read_lock() with buffer->mutex and cpu_buffer->mapping_lock Mapping the ring buffer to user space uses the cpu_buffer->mapping_lock. The buffer->mutex can be taken when the mapping_lock is held, giving the locking order of: cpu_buffer->mapping_lock -->> buffer->mutex. But there also exists the ordering: buffer->mutex -->> cpus_read_lock() mm->mmap_lock -->> cpu_buffer->mapping_lock cpus_read_lock() -->> mm->mmap_lock causing a circular chain of: cpu_buffer->mapping_lock -> buffer->mutex -->> cpus_read_lock() -->> mm->mmap_lock -->> cpu_buffer->mapping_lock By moving the cpus_read_lock() outside the buffer->mutex where: cpus_read_lock() -->> buffer->mutex, breaks the deadlock chain. - Do not trigger WARN_ON() for commit overrun When the ring buffer is user space mapped and there's a "commit overrun" (where an interrupt preempted an event, and then added so many events it filled the buffer having to drop events when it hit the preempted event) a WARN_ON() was triggered if this was read via a memory mapped buffer. This is due to "missed events" being non zero when the reader page ended up with the commit page. The idea was, if the writer is on the reader page, there's only one page that has been written to and there should be no missed events. But if a commit overrun is done where the writer is off the commit page and looped around to the commit page causing missed events, it is possible that the reader page is the commit page with missed events. Instead of triggering a WARN_ON() when the reader page is the commit page with missed events, trigger it when the reader page is the tail_page with missed events. That's because the writer is always on the tail_page if an event was interrupted (which holds the commit event) and continues off the commit page. - Reset the persistent buffer if it is fully consumed On boot up, if the user fully consumes the last boot buffer of the persistent buffer, if it reboots without enabling it, there will still be events in the buffer which can cause confusion. Instead, reset the buffer when it is fully consumed, so that the data is not read again. - Clean up some goto out jumps There's a few cases that the code jumps to the "out:" label that simply returns a value. There used to be more work done at those labels but now that they simply return a value use a return instead of jumping to a label. - Use guard() to simplify some of the code Add guard() around some locking instead of jumping to a label to do the unlocking. - Use free() to simplify some of the code Use free(kfree) on variables that will get freed on error and use return_ptr() to return the variable when its not freed. There's one instance where free(kfree) simplifies the code on a temp variable that was allocated just for the function use. * tag 'trace-ringbuffer-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Simplify functions with __free(kfree) to free allocations ring-buffer: Make ring_buffer_{un}map() simpler with guard(mutex) ring-buffer: Simplify ring_buffer_read_page() with guard() ring-buffer: Simplify reset_disabled_cpu_buffer() with use of guard() ring-buffer: Remove jump to out label in ring_buffer_swap_cpu() ring-buffer: Removed unnecessary if() goto out where out is the next line tracing: Reset last-boot buffers when reading out all cpu buffers ring-buffer: Allow reserve_mem persistent ring buffers to be mmapped ring-buffer: Do not trigger WARN_ON() due to a commit_overrun ring-buffer: Move cpus_read_lock() outside of buffer->mutex
2025-05-30Merge tag 'pull-automount' of ↵Linus Torvalds1-4/+15
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull automount updates from Al Viro: "Automount wart removal A bunch of odd boilerplate gone from instances - the reason for those was the need to protect the yet-to-be-attched mount from mark_mounts_for_expiry() deciding to take it out. But that's easy to detect and take care of in mark_mounts_for_expiry() itself; no need to have every instance simulate mount being busy by grabbing an extra reference to it, with finish_automount() undoing that once it attaches that mount. Should've done it that way from the very beginning... This is a flagday change, thankfully there are very few instances. vfs_submount() is gone - its sole remaining user (trace_automount) had been switched to saner primitives" * tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: kill vfs_submount() saner calling conventions for ->d_automount()
2025-05-29Merge tag 'trace-v6.16' of ↵Linus Torvalds1-42/+172
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - Have module addresses get updated in the persistent ring buffer The addresses of the modules from the previous boot are saved in the persistent ring buffer. If the same modules are loaded and an address is in the old buffer points to an address that was both saved in the persistent ring buffer and is loaded in memory, shift the address to point to the address that is loaded in memory in the trace event. - Print function names for irqs off and preempt off callsites When ignoring the print fmt of a trace event and just printing the fields directly, have the fields for preempt off and irqs off events still show the function name (via kallsyms) instead of j