linux/kernel/trace, branch v6.16

Merge tag 'trace-v6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-07-20T20:03:31Z

Pull tracing fixes from Steven Rostedt: - Fix timerlat with use of FORTIFY_SOURCE FORTIFY_SOURCE was added to the stack tracer where it compares the entry->caller array to having entry->size elements. timerlat has the following: memcpy(&entry->caller, fstack->calls, size); entry->size = size; Which triggers FORTIFY_SOURCE as the caller is populated before the entry->size is initialized. Swap the order to satisfy FORTIFY_SOURCE logic. - Add down_write(trace_event_sem) when adding trace events in modules Trace events being added to the ftrace_events array are protected by the trace_event_sem semaphore. But when loading modules that have trace events, the addition of the events are not protected by the semaphore and loading two modules that have events at the same time can corrupt the list. Also add a lockdep_assert_held(trace_event_sem) to _trace_add_event_dirs() to confirm it is held when iterating the list. * tag 'trace-v6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Add down_write(trace_event_sem) when adding trace event tracing/osnoise: Fix crash in timerlat_dump_stack()

tracing: Add down_write(trace_event_sem) when adding trace event

2025-07-19T17:54:59Z

When a module is loaded, it adds trace events defined by the module. It may also need to modify the modules trace printk formats to replace enum names with their values. If two modules are loaded at the same time, the adding of the event to the ftrace_events list can corrupt the walking of the list in the code that is modifying the printk format strings and crash the kernel. The addition of the event should take the trace_event_sem for write while it adds the new event. Also add a lockdep_assert_held() on that semaphore in __trace_add_event_dirs() as it iterates the list. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/20250718223158.799bfc0c@batman.local.home Reported-by: Fusheng Huang(黄富生) Closes: https://lore.kernel.org/all/20250717105007.46ccd18f@batman.local.home/ Fixes: 110bf2b764eb6 ("tracing: add protection around module events unload") Signed-off-by: Steven Rostedt (Google)

tracing/osnoise: Fix crash in timerlat_dump_stack()

2025-07-18T19:51:35Z

We have observed kernel panics when using timerlat with stack saving, with the following dmesg output: memcpy: detected buffer overflow: 88 byte write of buffer size 0 WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0 CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy) Call Trace: ? trace_buffer_lock_reserve+0x2a/0x60 __fortify_panic+0xd/0xf __timerlat_dump_stack.cold+0xd/0xd timerlat_dump_stack.part.0+0x47/0x80 timerlat_fd_read+0x36d/0x390 vfs_read+0xe2/0x390 ? syscall_exit_to_user_mode+0x1d5/0x210 ksys_read+0x73/0xe0 do_syscall_64+0x7b/0x160 ? exc_page_fault+0x7e/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e __timerlat_dump_stack() constructs the ftrace stack entry like this: struct stack_entry *entry; ... memcpy(&entry->caller, fstack->calls, size); entry->size = fstack->nr_entries; Since commit e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure"), struct stack_entry marks its caller field with __counted_by(size). At the time of the memcpy, entry->size contains garbage from the ringbuffer, which under some circumstances is zero, triggering a kernel panic by buffer overflow. Populate the size field before the memcpy so that the out-of-bounds check knows the correct size. This is analogous to __ftrace_trace_stack(). Cc: stable@vger.kernel.org Cc: John Kacur Cc: Luis Goncalves Cc: Attila Fazekas Link: https://lore.kernel.org/20250716143601.7313-1-tglozar@redhat.com Fixes: e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure") Signed-off-by: Tomas Glozar Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

tracing/probes: Avoid using params uninitialized in parse_btf_arg()

2025-07-16T05:01:54Z

After a recent change in clang to strengthen uninitialized warnings [1], it points out that in one of the error paths in parse_btf_arg(), params is used uninitialized: kernel/trace/trace_probe.c:660:19: warning: variable 'params' is uninitialized when used here [-Wuninitialized] 660 | return PTR_ERR(params); | ^~~~~~ Match many other NO_BTF_ENTRY error cases and return -ENOENT, clearing up the warning. Link: https://lore.kernel.org/all/20250715-trace_probe-fix-const-uninit-warning-v1-1-98960f91dd04@kernel.org/ Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2110 Fixes: d157d7694460 ("tracing/probes: Support BTF field access from $retval") Link: https://github.com/llvm/llvm-project/commit/2464313eef01c5b1edf0eccf57a32cdee01472c7 [1] Signed-off-by: Nathan Chancellor Signed-off-by: Masami Hiramatsu (Google)

tracing: Fix filter logic error

2025-06-27T19:51:36Z

If the processing of the tr->events loop fails, the filter that has been added to filter_head will be released twice in free_filter_list(&head->rcu) and __free_filter(filter). After adding the filter of tr->events, add the filter to the filter_head process to avoid triggering uaf. Link: https://lore.kernel.org/tencent_4EF87A626D702F816CD0951CE956EC32CD0A@qq.com Fixes: a9d0aab5eb33 ("tracing: Fix regression of filter waiting a long time on RCU synchronization") Reported-by: syzbot+daba72c4af9915e9c894@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=daba72c4af9915e9c894 Tested-by: syzbot+daba72c4af9915e9c894@syzkaller.appspotmail.com Acked-by: Masami Hiramatsu (Google) Signed-off-by: Edward Adam Davis Signed-off-by: Steven Rostedt (Google)

fgraph: Do not enable function_graph tracer when setting funcgraph-args

2025-06-18T11:43:22Z

When setting the funcgraph-args option when function graph tracer is net enabled, it incorrectly enables it. Worse, it unregisters itself when it was never registered. Then when it gets enabled again, it will register itself a second time causing a WARNing. ~# echo 1 > /sys/kernel/tracing/options/funcgraph-args ~# head -20 /sys/kernel/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 813/26317372 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | -0 [007] d..4. 358.966010: 7) 1.692 us | fetch_next_timer_interrupt(basej=4294981640, basem=357956000000, base_local=0xffff88823c3ae040, base_global=0xffff88823c3af300, tevt=0xffff888100e47cb8); -0 [007] d..4. 358.966012: 7) | tmigr_cpu_deactivate(nextexp=357988000000) { -0 [007] d..4. 358.966013: 7) | _raw_spin_lock(lock=0xffff88823c3b2320) { -0 [007] d..4. 358.966014: 7) 0.981 us | preempt_count_add(val=1); -0 [007] d..5. 358.966017: 7) 1.058 us | do_raw_spin_lock(lock=0xffff88823c3b2320); -0 [007] d..4. 358.966019: 7) 5.824 us | } -0 [007] d..5. 358.966021: 7) | tmigr_inactive_up(group=0xffff888100cb9000, child=0x0, data=0xffff888100e47bc0) { -0 [007] d..5. 358.966022: 7) | tmigr_update_events(group=0xffff888100cb9000, child=0x0, data=0xffff888100e47bc0) { Notice the "tracer: nop" at the top there. The current tracer is the "nop" tracer, but the content is obviously the function graph tracer. Enabling function graph tracing will cause it to register again and trigger a warning in the accounting: ~# echo function_graph > /sys/kernel/tracing/current_tracer -bash: echo: write error: Device or resource busy With the dmesg of: ------------[ cut here ]------------ WARNING: CPU: 7 PID: 1095 at kernel/trace/ftrace.c:3509 ftrace_startup_subops+0xc1e/0x1000 Modules linked in: kvm_intel kvm irqbypass CPU: 7 UID: 0 PID: 1095 Comm: bash Not tainted 6.16.0-rc2-test-00006-gea03de4105d3 #24 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ftrace_startup_subops+0xc1e/0x1000 Code: 48 b8 22 01 00 00 00 00 ad de 49 89 84 24 88 01 00 00 8b 44 24 08 89 04 24 e9 c3 f7 ff ff c7 04 24 ed ff ff ff e9 b7 f7 ff ff <0f> 0b c7 04 24 f0 ff ff ff e9 a9 f7 ff ff c7 04 24 f4 ff ff ff e9 RSP: 0018:ffff888133cff948 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 1ffff1102679ff31 RCX: 0000000000000000 RDX: 1ffffffff0b27a60 RSI: ffffffff8593d2f0 RDI: ffffffff85941140 RBP: 00000000000c2041 R08: ffffffffffffffff R09: ffffed1020240221 R10: ffff88810120110f R11: ffffed1020240214 R12: ffffffff8593d2f0 R13: ffffffff8593d300 R14: ffffffff85941140 R15: ffffffff85631100 FS: 00007f7ec6f28740(0000) GS:ffff8882b5251000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7ec6f181c0 CR3: 000000012f1d0005 CR4: 0000000000172ef0 Call Trace: ? __pfx_ftrace_startup_subops+0x10/0x10 ? find_held_lock+0x2b/0x80 ? ftrace_stub_direct_tramp+0x10/0x10 ? ftrace_stub_direct_tramp+0x10/0x10 ? trace_preempt_on+0xd0/0x110 ? __pfx_trace_graph_entry_args+0x10/0x10 register_ftrace_graph+0x4d2/0x1020 ? tracing_reset_online_cpus+0x14b/0x1e0 ? __pfx_register_ftrace_graph+0x10/0x10 ? ring_buffer_record_enable+0x16/0x20 ? tracing_reset_online_cpus+0x153/0x1e0 ? __pfx_tracing_reset_online_cpus+0x10/0x10 ? __pfx_trace_graph_return+0x10/0x10 graph_trace_init+0xfd/0x160 tracing_set_tracer+0x500/0xa80 ? __pfx_tracing_set_tracer+0x10/0x10 ? lock_release+0x181/0x2d0 ? _copy_from_user+0x26/0xa0 tracing_set_trace_write+0x132/0x1e0 ? __pfx_tracing_set_trace_write+0x10/0x10 ? ftrace_graph_func+0xcc/0x140 ? ftrace_stub_direct_tramp+0x10/0x10 ? ftrace_stub_direct_tramp+0x10/0x10 ? ftrace_stub_direct_tramp+0x10/0x10 vfs_write+0x1d0/0xe90 ? __pfx_vfs_write+0x10/0x10 Have the setting of the funcgraph-args check if function_graph tracer is the current tracer of the instance, and if not, do nothing, as there's nothing to do (the option is checked when function_graph tracing starts). Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Cc: Mark Rutland Link: https://lore.kernel.org/20250618073801.057ea636@gandalf.local.home Fixes: c7a60a733c373 ("ftrace: Have funcgraph-args take affect during tracing") Closes: https://lore.kernel.org/all/4ab1a7bdd0174ab09c7b0d68cdbff9a4@huawei.com/ Reported-by: Changbin Du Tested-by: Changbin Du Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

tracing: Do not free "head" on error path of filter_free_subsystem_filters()

2025-06-10T13:39:58Z

The variable "head" is allocated and initialized as a list before allocating the first "item" for the list. If the allocation of "item" fails, it frees "head" and then jumps to the label "free_now" which will process head and free it. This will cause a UAF of "head", and it doesn't need to free it before jumping to the "free_now" label as that code will free it. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250610093348.33c5643a@gandalf.local.home Fixes: a9d0aab5eb33 ("tracing: Fix regression of filter waiting a long time on RCU synchronization") Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202506070424.lCiNreTI-lkp@intel.com/ Signed-off-by: Steven Rostedt (Google)

Merge tag 'trace-v6.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-06-08T15:19:01Z

Pull more tracing fixes from Steven Rostedt: - Fix regression of waiting a long time on updating trace event filters When the faultable trace points were added, it needed task trace RCU synchronization. This was added to the tracepoint_synchronize_unregister() function. The filter logic always called this function whenever it updated the trace event filters before freeing the old filters. This increased the time of "trace-cmd record" from taking 13 seconds to running over 2 minutes to complete. Move the freeing of the filters to call_rcu*() logic, which brings the time back down to 13 seconds. - Fix ring_buffer_subbuf_order_set() error path lock protection The error path of the ring_buffer_subbuf_order_set() released the mutex too early and allowed subsequent accesses to setting the subbuffer size to corrupt the data and cause a bug. By moving the mutex locking to the end of the error path, it prevents the reentrant access to the critical data and also allows the function to convert the taking of the mutex over to the guard() logic. - Remove unused power management clock events The clock events were added in 2010 for power management. In 2011 arm used them. In 2013 the code they were used in was removed. These events have been wasting memory since then. - Fix sparse warnings There was a few places that sparse warned about trace_events_filter.c where file->filter was referenced directly, but it is annotated with an __rcu tag. Use the helper functions and fix them up to use rcu_dereference() properly. * tag 'trace-v6.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Add rcu annotation around file->filter accesses tracing: PM: Remove unused clock events ring-buffer: Fix buffer locking in ring_buffer_subbuf_order_set() tracing: Fix regression of filter waiting a long time on RCU synchronization

tracing: Add rcu annotation around file->filter accesses

2025-06-07T14:31:22Z

Running sparse on trace_events_filter.c triggered several warnings about file->filter being accessed directly even though it's annotated with __rcu. Add rcu_dereference() around it and shuffle the logic slightly so that it's always referenced via accessor functions. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250607102821.6c7effbf@gandalf.local.home Signed-off-by: Steven Rostedt (Google)

Merge tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2025-06-07T01:05:18Z

Pull RISC-V updates from Palmer Dabbelt: - Support for the FWFT SBI extension, which is part of SBI 3.0 and a dependency for many new SBI and ISA extensions - Support for getrandom() in the VDSO - Support for mseal - Optimized routines for raid6 syndrome and recovery calculations - kexec_file() supports loading Image-formatted kernel binaries - Improvements to the instruction patching framework to allow for atomic instruction patching, along with rules as to how systems need to behave in order to function correctly - Support for a handful of new ISA extensions: Svinval, Zicbop, Zabha, some SiFive vendor extensions - Various fixes and cleanups, including: misaligned access handling, perf symbol mangling, module loading, PUD THPs, and improved uaccess routines * tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (69 commits) riscv: uaccess: Only restore the CSR_STATUS SUM bit RISC-V: vDSO: Wire up getrandom() vDSO implementation riscv: enable mseal sysmap for RV64 raid6: Add RISC-V SIMD syndrome and recovery calculations riscv: mm: Add support for Svinval extension RISC-V: Documentation: Add enough title underlines to CMODX riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE MAINTAINERS: Update Atish's email address riscv: uaccess: do not do misaligned accesses in get/put_user() riscv: process: use unsigned int instead of unsigned long for put_user() riscv: make unsafe user copy routines use existing assembly routines riscv: hwprobe: export Zabha extension riscv: Make regs_irqs_disabled() more clear perf symbols: Ignore mapping symbols on riscv RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND riscv: module: Optimize PLT/GOT entry counting riscv: Add support for PUD THP riscv: xchg: Prefetch the destination word for sc.w riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop riscv: Add support for Zicbop ...