summaryrefslogtreecommitdiff
path: root/kernel/trace
AgeCommit message (Collapse)Author
10 daystracing/osnoise: Call synchronize_rcu() when unregisteringCrystal Wood
commit fe58f457ad8d0a2bef4e053cfecca4b5cd266b1a upstream. This ensures that any RCU readers traversing the instance list have finished, before releasing the reference on the tracer that the instance points to. Cc: stable@vger.kernel.org Fixes: a6ed2aee54644 ("tracing: Switch to kvfree_rcu() API") Link: https://patch.msgid.link/20260609045430.1589786-1-crwood@redhat.com Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Crystal Wood <crwood@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daystracing/probes: Fix double addition of offset for @+FOFFSETMasami Hiramatsu (Google)
commit 9a667b7750dda88cbf1cca96a53a2163b2ee71f7 upstream. Since commit 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code") wrongly use @offset local variable during the parsing, the offset value is added twice when dereferencing. Reset the @offset after setting it in FETCH_OP_FOFFS. Link: https://lore.kernel.org/all/178217905962.643090.1978577464942171332.stgit@devnote2/ Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daystracing/user_events: Fix use-after-free in user_event_mm_dup()Michael Bommarito
commit 50fd6dd755c6e48a38af2fa4621167eea56829c2 upstream. user_event_mm_dup() walks the parent mm's enabler list locklessly under rcu_read_lock() during fork() (from copy_process()); it does not take event_mutex: rcu_read_lock(); list_for_each_entry_rcu(enabler, &old_mm->enablers, mm_enablers_link) enabler->event = user_event_get(orig->event); user_event_enabler_destroy() removes an enabler from that list with list_del_rcu() and then, without waiting for a grace period, drops the enabler's user_event reference with user_event_put() and frees the enabler with kfree(). A reader that loaded the enabler before the list_del_rcu() can still be walking it, which leads to two use-after-frees: - kfree(enabler) frees the enabler while that reader dereferences enabler->event. - user_event_put() may drop the last reference to the user_event, which is then freed (via delayed_destroy_user_event() on a work queue), while the same reader does user_event_get(orig->event) on it. Both are reachable by an unprivileged task that can open user_events_data: one multithreaded process that registers an enabler and then concurrently unregisters it and calls fork() triggers the race. KASAN reports a slab-use-after-free in user_event_mm_dup() during clone(), with a "refcount_t: addition on 0" warning when the user_event is freed. The enabler use-after-free was found first; the user_event one was reported by XIAO WU, and the earlier enabler-only fix did not address it. Defer both the user_event_put() and the kfree(enabler) to a work item queued with queue_rcu_work(), so they run only after an RCU grace period, once all readers walking the enabler list have finished. The put must run in process context because user_event_put() takes event_mutex on the last reference, so a work queue is used rather than call_rcu(). The now-unlocked put lets the locked argument of user_event_enabler_destroy() be removed; all callers are updated. Fixes: 7235759084a4 ("tracing/user_events: Use remote writes for event enablement") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260707165912.2560537-2-michael.bommarito@gmail.com Reported-by: XIAO WU <xiaowu.417@qq.com> Closes: https://lore.kernel.org/all/tencent_89647CE40DC452B891C65C94D1B271DE8E07@qq.com/ Suggested-by: Beau Belgrave <beaub@linux.microsoft.com> Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysbpf: Add missing access_ok call to copy_user_symsJiri Olsa
commit d5dc200c3a3f217de072af269dd90adddf90e48d upstream. As reported by sashiko we use __get_user without prior access_ok call on the user space pointer. Adding the missing call for the whole pointer array. Plus removing the err check in the error path, because it's not needed and also we can return -ENOMEM directly from the first kvmalloc_array fail path. Cc: stable@vger.kernel.org [1] https://lore.kernel.org/bpf/20260611115503.AC16D1F00893@smtp.kernel.org/ Fixes: 0236fec57a15 ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link") Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://lore.kernel.org/bpf/20260611115503.AC16D1F00893@smtp.kernel.org/ Signed-off-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260616083056.405652-1-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysring-buffer: Allow sparse CPU masks in ring_buffer_desc()Vincent Donnefort
[ Upstream commit 601ddaceb861be7eb557278109966320a6f3478c ] No user currently relies on sparse CPU masks, but the descriptor logic already supports them via linear fallback. Remove the arbitrary limitation. Link: https://patch.msgid.link/20260709160017.1729517-4-vdonnefort@google.com Fixes: 2e67fabd8b77 ("ring-buffer: Introduce ring-buffer remotes") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/remotes: Fix struct_len in trace_remote_alloc_buffer()Vincent Donnefort
[ Upstream commit d471d4f86e8689ad15309e49da8e5e4e9bb9ce87 ] Pre-calculate desc->struct_len up-front in trace_remote_alloc_buffer() with trace_buffer_desc_size() to fix double-counting. While at it, use the accessor __first_ring_buffer_desc(). Link: https://patch.msgid.link/20260709160017.1729517-3-vdonnefort@google.com Fixes: 96e43537af54 ("tracing: Introduce trace remotes") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/remotes: Fix leak in trace_remote_alloc_buffer() error pathVincent Donnefort
[ Upstream commit ec082d0b978b5fb4c11205ccce63587ac94c74e1 ] If page allocation fails in trace_remote_alloc_buffer(), desc->nr_cpus is not yet incremented for the current CPU. As a consequence, on error, half-allocated rb_desc will not be freed in trace_remote_free_buffer(). Increment desc->nr_cpus as soon as the first allocation for the current CPU has succeeded. Link: https://patch.msgid.link/20260709160017.1729517-2-vdonnefort@google.com Fixes: 96e43537af54 ("tracing: Introduce trace remotes") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing: Make tracepoint_printk static as not exportedBen Dooks
[ Upstream commit d5c6785f94ead7cd76b38af301ac63cb673485bc ] The tracepoint_printk symbol is not exported, so make it static to remove the following sparse warning: kernel/trace/trace.c:90:5: warning: symbol 'tracepoint_printk' was not declared. Should it be static? Fixes: dd293df6395a2 ("tracing: Move trace sysctls into trace.c") Link: https://patch.msgid.link/20260617105822.904164-1-ben.dooks@codethink.co.uk Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daysring-buffer: Fix event length with forced 8-byte alignmentHui Wang
[ Upstream commit c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0 ] When RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length() reserves the space of event->array[0] for placing the data length and rb_update_event() stores the data length in event->array[0] accordingly. As a result the whole event length will add extra 4 bytes for sizeof(event.array[0]) unconditionally. But ring_buffer_event_length() only subtracts the sizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA + sizeof(event->array[0]). As a result, small events on architectures with RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4 bytes larger than expected. To fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract the size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is true. This issue is observed in a riscv64 kernel with CONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest trace_marker_raw.tc, we get the weird log: for cases where the id is 1..100, the number of data field is 8*N, but once id exceeds 100, the number of data field becomes 8*N+4: # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1) ... # a buf: 58 ... (number of data field is 8*2) ... # 64 buf: 58 ... (number of data field is 8*13) # 65 buf: 58 ... (number of data field is 8*13+4) After applying this change, the number of data field keeps being 8*N+4 consistently. Link: https://patch.msgid.link/20260607072431.125633-2-hui.wang@canonical.com Fixes: 2271048d1b3b ("ring-buffer: Do 8 byte alignment for 64 bit that can not handle 4 byte align") Signed-off-by: Hui Wang <hui.wang@canonical.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/probes: Make the $ prefix mandatory for comm accessMasami Hiramatsu (Google)
[ Upstream commit a369299c3f785cf556bbef2de2db0aa2d294c4c9 ] Since $comm or $COMM are not event field but special fetcharg variables to access current->comm, It should not be accessed without '$' prefix even with typecast. Link: https://lore.kernel.org/all/178231209724.732967.12049805699091810641.stgit@devnote2/ Fixes: 69efd863a785 ("tracing/eprobes: Allow use of BTF names to dereference pointers") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/fprobe: Fix NULL pointer dereference in fprobe_fgraph_entry()Sechang Lim
[ Upstream commit 367c49d6e283c17b56a31e7a8d964a079244264c ] fprobe_fgraph_entry() sizes a shadow-stack reservation in one walk of the per-ip fprobe list and fills it in a second walk, both under rcu_read_lock() only. A fprobe registered on an already-live ip can become visible between the two walks, so the fill walk processes an exit_handler the sizing walk did not count and used runs past reserved_words. If the sizing walk counted nothing, fgraph_data is NULL and the first write_fprobe_header() faults: Oops: general protection fault, probably for non-canonical address ... KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:fprobe_fgraph_entry+0xa38/0xf10 kernel/trace/fprobe.c:167 Call Trace: <TASK> function_graph_enter_regs+0x44c/0xa10 kernel/trace/fgraph.c:677 ftrace_graph_func+0xc5/0x140 arch/x86/kernel/ftrace.c:671 __kernel_text_address+0x9/0x40 kernel/extable.c:78 arch_stack_walk+0x117/0x170 arch/x86/kernel/stacktrace.c:26 kmem_cache_free+0x188/0x580 mm/slub.c:6378 tcp_data_queue+0x18d/0x6550 net/ipv4/tcp_input.c:5590 [...] </TASK> The list cannot be frozen across the two walks, so skip a node that does not fit the reservation and count it as missed. Link: https://lore.kernel.org/all/20260619184425.3824774-1-rhkrqnwk98@gmail.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing: eprobe: read the complete FILTER_PTR_STRING pointerMartin Kaiser
[ Upstream commit 206b25c09080cc20fd4c2bea12d59df4b7ba2121 ] For a char * element in an event, the FILTER_PTR_STRING filter type is used. When the event occurs, a pointer is stored in the ringbuffer. If an eprobe references such a char * element of a "base event", the stored pointer is truncated when it's read from the ringbuffer. $ cd /sys/kernel/tracing $ echo 'e rcu.rcu_utilization $s:x64 $s:string' > dynamic_events $ echo 1 > tracing_on $ echo 1 > events/eprobes/enable $ sleep 1 $ echo 0 > events/eprobes/enable $ cat trace <idle>-0 ...: (rcu.rcu_utilization) arg1=0x4f arg2=(fault) <idle>-0 ...: (rcu.rcu_utilization) arg1=0x2 arg2=(fault) The problem is in get_event_field val = (unsigned long)(*(char *)addr); addr points to the position in the ringbuffer where the pointer was stored. The assignment reads only the lowest byte of the pointer. Fix the cast to read the whole pointer. The output of the test above is now <idle>-0 ... arg1=0xffffffff81c7d3f3 arg2="Start scheduler-tick" <idle>-0 ... arg1=0xffffffff81c57340 arg2="End scheduler-tick" Link: https://lore.kernel.org/all/20260620145339.3234726-1-martin@kaiser.cx/ Fixes: f04dec93466a ("tracing/eprobes: Fix reading of string fields") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/probes: Remove WARN_ON_ONCE from parse_btf_argMasami Hiramatsu (Google)
[ Upstream commit 251a8fe1b9aedccd298b77bc28426d564c5a923f ] Sashiko found that user can cause this WARN_ON_ONCE() easily with adding a kprobe event based on a raw address with BTF parameter. Since this is not an unexpected condition, remove the WARN_ON_ONCE(). Link: https://lore.kernel.org/all/178177265367.2059927.13789953014706792126.stgit@mhiramat.tok.corp.google.com/ Link: https://sashiko.dev/#/patchset/178165816303.269421.7302603996990753309.stgit%40devnote2 Reported-by: Sashiko <sashiko-bot@kernel.org> Fixes: b576e09701c7 ("tracing/probes: Support function parameters if BTF is available") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing/eprobes: Allow use of BTF names to dereference pointersSteven Rostedt
[ Upstream commit 69efd863a78584b9416ed6be0e1e7349124b4a00 ] Add syntax to the parsing of eprobes to be able to typecast a trace event field that is a pointer to a structure. Currently, a dereference must be a number, where the user has to figure out manually the offset of a member of a structure that they want to dereference. But for event probes that records a field that happens to be a pointer to a structure, it cannot dereference these values with BTF naming, but must use numerical offsets. For example, to find out what device a sk_buff is pointing to in the net_dev_xmit trace event, one must first use gdb to find the offsets of the members of the structures: (gdb) p &((struct sk_buff *)0)->dev $1 = (struct net_device **) 0x10 (gdb) p &((struct net_device *)0)->name $2 = (char (*)[16]) 0x118 And then use the raw numbers to dereference: # echo 'e:xmit net.net_dev_xmit +0x118(+0x10($skbaddr)):string' >> dynamic_events If BTF is in the kernel, then instead, the skbaddr can be typecast to sk_buff and use the normal dereference logic. # echo 'e:xmit net.net_dev_xmit (sk_buff)skbaddr->dev->name:string' >> dynamic_events # echo 1 > events/eprobes/xmit/enable # cat trace [..] sshd-session-1022 [000] b..2. 860.249343: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.250061: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.250142: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.263553: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.283820: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.302716: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.322905: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.342828: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.362268: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.382335: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.400856: xmit: (net.net_dev_xmit) arg1="enp7s0" sshd-session-1022 [000] b..2. 860.419893: xmit: (net.net_dev_xmit) arg1="enp7s0" The syntax is simply: (STRUCT)(FIELD)->MEMBER[->MEMBER..] Also add comments around the #else and #endif of #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS to know what they are for. Link: https://lore.kernel.org/all/20260601130746.2139d926@gandalf.local.home/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Stable-dep-of: 251a8fe1b9ae ("tracing/probes: Remove WARN_ON_ONCE from parse_btf_arg") Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing: probes: fix typo in a log messageMartin Kaiser
[ Upstream commit 72c8646956ffc8050bb8be5988a0f28fc37e1ac4 ] Fix a typo ("Invalid $-variable") in a log message. Link: https://lore.kernel.org/all/20260507081041.885781-4-martin@kaiser.cx/ Fixes: ab105a4fb894 ("tracing: Use tracing error_log with probe events") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daysbpf: Guard __get_user acesss with access_ok for uprobe_multi dataJiri Olsa
[ Upstream commit 4d87a251d45b4a95eb4c0abcfab809c9f231258a ] As reported by sashiko [1] we need to use access_ok to check the user space data bounds before we use __get-user to get it. [1] https://lore.kernel.org/bpf/20260610145235.CB1441F00893@smtp.kernel.org/ Fixes: 0b779b61f651 ("bpf: Add cookies support for uprobe_multi link") Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20260611114230.950379-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
10 daystracing: Bound synthetic-field strings with seq_bufPengpeng Hou
[ Upstream commit f07883450eb14d1cf020b55d9f3a7ec5683bcd26 ] The synthetic field helpers build a prefixed synthetic variable name and a generated hist command in fixed MAX_FILTER_STR_VAL buffers. The current code appends those strings with raw strcat(), so long key lists, field names, or saved filters can run past the end of the staging buffers. Build both strings with seq_buf and propagate -E2BIG if either the synthetic variable name or the generated command exceeds MAX_FILTER_STR_VAL. This keeps the existing tracing-side limit while using the helper intended for bounded command construction. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Link: https://patch.msgid.link/20260430043350.57928-1-pengpeng@iscas.ac.cn Fixes: 02205a6752f2 ("tracing: Add support for 'field variables'") Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn> [ sdr: Moved struct seq_buf *s for upside-down x-mas tree formatting ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-07-18tracing: Prevent out-of-bounds read in glob matchingHuihui Huang
commit 0a6070839b1ef276d5b05bedfb787743e140fb17 upstream. String event fields are not necessarily NUL-terminated, so the filter predicate functions (filter_pred_string(), filter_pred_strloc() and filter_pred_strrelloc()) pass the field length to the regex match callbacks, and the length-aware matchers honour it. regex_match_glob() was the exception: it ignored the length and called glob_match(), which scans the string until it hits a NUL byte. Some string fields are not NUL-terminated. One example is the dynamic char array of the xfs_* namespace tracepoints, which is copied without a trailing NUL. For such a field, glob matching reads past the end of the event field, causing a KASAN slab-out-of-bounds read in glob_match(), reached via regex_match_glob() and filter_match_preds() from the xfs_lookup tracepoint. Add a length-bounded glob_match_len() and use it from regex_match_glob() so glob matching always stops at the field boundary. The matching loop is factored into a shared helper so glob_match() keeps its behaviour. Fixes: 60f1d5e3bac4 ("ftrace: Support full glob matching") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/da1aaf125fc3b63320b0c540fd6afa7c3d5b4f1a.1782836943.git.hhhuang@smu.edu.sg Reported-by: Yuan Tan <yuantan098@gmail.com> Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Reported-by: Zhengchuan Liang <zcliangcn@gmail.com> Reported-by: Xin Liu <bird@lzu.edu.cn> Assisted-by: Codex:GPT-5.4 Signed-off-by: Huihui Huang <hhhuang@smu.edu.sg> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-18tracing: Fix NULL pointer dereference in func_set_flag()Yuanhe Shu
commit c3e94604675e3db186111b8942650d86577df9b0 upstream. func_set_flag() dereferences tr->current_trace_flags before verifying that the current tracer is actually the function tracer. When the active tracer has been switched away from "function" (e.g., to "wakeup_rt"), tr->current_trace_flags can be NULL, leading to a NULL pointer dereference and kernel crash. The call chain that triggers this is: trace_options_write() -> __set_tracer_option() -> trace->set_flag() /* func_set_flag */ In func_set_flag(), the first operation is: if (!!set == !!(tr->current_trace_flags->val & bit)) This dereferences tr->current_trace_flags unconditionally. The safety check that guards against a non-function tracer: if (tr->current_trace != &function_trace) return 0; is placed *after* the dereference, which is too late. This was observed with the following crash dump: BUG: unable to handle page fault at 0000000000000000 RIP: func_set_flag+0xd Call Trace: __set_tracer_option+0x27 trace_options_write+0x75 vfs_write+0x12a ksys_write+0x66 do_syscall_64+0x5b RIP: ffffffff914c973d RSP: ff67ec88b01dfdf0 RFLAGS: 00010202 RAX: 0000000000000000 RBX: ff3a826e80354580 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffff93918080 The disassembly confirms the fault: func_set_flag+0: mov 0x1f08(%rdi), %rax ; RAX = tr->current_trace_flags = NULL func_set_flag+13: mov (%rax), %eax ; page fault: dereference NULL At the time of the crash: tr->current_trace_flags = 0x0 (NULL) tr->current_trace = wakeup_rt_tracer (not function_trace) The scenario is that a process opens a function tracer option file (such as "func_stack_trace"), then the current tracer is switched to another tracer (e.g., "wakeup_rt"), which sets current_trace_flags to NULL. When the process subsequently writes to the option file, func_set_flag() is invoked and crashes on the NULL dereference. Fix this by moving the current_trace check before the current_trace_flags dereference, so that func_set_flag() returns early when the function tracer is not active. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260624061715.1445655-1-xiangzao@linux.alibaba.com Fixes: 76680d0d2825 ("tracing: Have function tracer define options per instance") Signed-off-by: Yuanhe Shu <xiangzao@linux.alibaba.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-09Merge tag 'trace-rv-v7.1-rc6-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull runtime verifier fixes from Steven Rostedt: - Fix reset ordering on per-task destruction Reset the task before dropping the slot instead of after, which was causing out-of-bound memory accesses. - Fix HA monitor synchronization and cleanup Ensure synchronous cleanup for HA monitors by running timer callbacks in RCU read-side critical sections and using synchronize_rcu() during destruction. - Avoid armed timers after tasks exit Add automatic cleanup for per-task HA monitors to prevent timers from firing after task exit. - Fix memory ordering for DA/HA monitors Fix race conditions during monitor start by using release-acquire semantics for the monitoring flag. - Fix initialization for DA/HA monitors Ensure monitors are not initialized relying on potentially corrupted state like the monitoring flag, that is not reset by all monitors type and may have an unknown state in monitors reusing the storage (per-task). - Fix memory safety in per-task and per-object monitors Prevent use-after-free and out-of-bounds access by synchronizing with in-flight tracepoint probes using tracepoint_synchronize_unregister() before freeing monitor storage or releasing task slots. - Adjust monitors for preemptible tracepoints Fix monitors that relied on tracepoints disabling preemption. Explicitly disable task migration when per-CPU monitors handle events to avoid accessing the wrong state and update the opid monitor logic. - Fix incorrect __user specifier usage Remove __user from a non-pointer variable in the extract_params() helper. - Fix bugs in the rv tool Ensure strings are NUL-terminated, fix substring matching in monitor searches, and improve cleanup and exit status handling. - Fix several bugs in rvgen Fix LTL literal stringification, subparsers' options handling, and suffix stripping in dot2k. * tag 'trace-rv-v7.1-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: verification/rvgen: Fix ltl2k writing True as a literal verification/rvgen: Fix options shared among commands verification/rvgen: Fix suffix strip in dot2k tools/rv: Fix cleanup after failed trace setup tools/rv: Fix substring match when listing container monitors tools/rv: Fix substring match bug in monitor name search tools/rv: Ensure monitor name and desc are NUL-terminated rv: Use 0 to check preemption enabled in opid rv: Prevent task migration while handling per-CPU events rv: Ensure synchronous cleanup for HA monitors rv: Add automatic cleanup handlers for per-task HA monitors rv: Do not rely on clean monitor when initialising HA rv: Fix monitor start ordering and memory ordering for monitoring flag rv: Ensure all pending probes terminate on per-obj monitor destroy rv: Prevent in-flight per-task handlers from using invalid slots rv: Reset per-task DA monitors before releasing the slot rv: Fix __user specifier usage in extract_params()
2026-06-03rv: Use 0 to check preemption enabled in opidGabriele Monaco
Tracepoint handlers no longer run with preemption disabled by default since a46023d5616 ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast"), the opid monitor should now count 1 in the preemption count as preemption disabled. Change the rule for preempt_off to preempt > 0. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-11-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Add automatic cleanup handlers for per-task HA monitorsGabriele Monaco
Hybrid automata monitors may start timers, depending on the model, these may remain active on an exiting task and cause false positives or even access freed memory. Add an enable/disable hook in the HA code, currently only populated by the per-task handler for registration and deregistration. This hooks to the sched_process_exit event and ensures the timer is stopped for every exiting task. The handler is enabled automatically but may be disabled, for instance if the monitor uses the event for another purpose (but should still manually ensure timers are stopped). Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type") Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Fix __user specifier usage in extract_params()Gabriele Monaco
The attributes variables extracted from syscalls in the helper are both defined with the __user specifier although only the actual pointer to user data should be marked. Remove the __user specifier from attr. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202604150820.Ny143u6X-lkp@intel.com Fixes: b133207deb72 ("rv: Add nomiss deadline monitor") Reviewed-by: Wen Yang <wen.yang@linux.dev> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-2-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-05-30tracing/probes: Point the error offset correctly for eprobe argument errorMasami Hiramatsu (Google)
Fix to point the error offset correctly for eprobe argument error. In the cleanup commit 1b8b0cd754cd ("tracing/probes: Move event parameter fetching code to common parser"), due to incorrect backward compatibility aimed at conforming to the test specifications, the error location was set to 0 when a non-existent formal parameter was specified for Eprobe. However, this should be corrected in both the test and the implementation to point correct error position. Link: https://lore.kernel.org/all/177967567399.209006.1451571244515632097.stgit@devnote2/ Fixes: 1b8b0cd754cd ("tracing/probes: Move event parameter fetching code to common parser") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-22Merge tag 'trace-v7.1-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Avoid NULL return from hist_field_name() The function hist_field_name() is directly passed to a strcat() which does not handle "NULL" characters. Return a zero length string when size is greater than the limit. This is used only to output already created histograms and no field currently is greater than the limit. But it should still not return NULL. - Do not call map->ops->elt_free() on allocation failure When elt_alloc() fails, it should not call the map->ops->elt_free() function if it exists, as that function may not be able to handle the free on allocation failures. The ->elt_free() should only be called when elt_alloc() succeeds. * tag 'trace-v7.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Do not call map->ops->elt_free() if elt_alloc() fails tracing: Avoid NULL return from hist_field_name() on truncation
2026-05-21tracing: Do not call map->ops->elt_free() if elt_alloc() failsMasami Hiramatsu (Google)
In paths where tracing_map_elt_alloc() failed to allocate objects, the map->ops->elt_alloc() call was never successful. In this case, map->ops->elt_free() should not be called. Link: https://sashiko.dev/#/patchset/20260520223101.34710-1-rosenp%40gmail.com Cc: stable@vger.kernel.org Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Rosen Penev <rosenp@gmail.com> Reported-by: Sashiko <sashiko-bot@kernel.org> Fixes: 2734b629525a ("tracing: Add per-element variable support to tracing_map") Link: https://patch.msgid.link/177933895460.108746.5396070821443932634.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21tracing: Create output file from cmd_check_undefinedThomas Weißschuh
As the output file is currently never created, the check will run every time, even if the inputs have not changed. Create an empty output file which allows make to skip the execution when it is not necessary. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Link: https://patch.msgid.link/20260520-tracing-ringbuffer-check-v1-1-d979cfab1338@weissschuh.net Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer") Fixes: 58b4bd18390e ("tracing: Adjust cmd_check_undefined to show unexpected undefined symbols") Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21tracing: Fix unload_page for simple_ring_buffer init rollbackVincent Donnefort
The unload_page callback expects the return value of load_page() as its argument: ret = load_page(va); unload(ret). Fix the rollback code in simple_ring_buffer_init_mm() where the descriptor's VA is used instead of the loaded page address. Link: https://patch.msgid.link/20260512141614.1759430-1-vdonnefort@google.com Fixes: 635923081c79 ("tracing: load/unload page callbacks for simple_ring_buffer") Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21tracing: Fix nr_subbufs initialization in simple_ring_buffer_init_mm()David Carlier
nr_subbufs in the ring buffer metadata is always initialized to zero because it is assigned from cpu_buffer->nr_pages before the page initialization loop has run. While nr_subbufs is not currently read by the kernel, it should reflect the actual buffer geometry in the meta page for correctness. Move the assignment after the page loop so that cpu_buffer->nr_pages holds the final count. Link: https://patch.msgid.link/20260512135420.99194-1-devnexen@gmail.com Fixes: 34e5b958bdad ("tracing: Introduce simple_ring_buffer") Reviewed-by: Vincent Donnefort <vdonnefort@google.com> Assisted-by: Claude:claude-opus-4-7 Signed-off-by: David Carlier <devnexen@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21ring-buffer: Flush and stop persistent ring buffer on panicMasami Hiramatsu (Google)
On real hardware, panic and machine reboot may not flush hardware cache to memory. This means the persistent ring buffer, which relies on a coherent state of memory, may not have its events written to the buffer and they may be lost. Moreover, there may be inconsistency with the counters which are used for validation of the integrity of the persistent ring buffer which may cause all data to be discarded. To avoid this issue, stop recording of the ring buffer on panic and flush the cache of the ring buffer's memory. Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Cc: stable@vger.kernel.org Cc: Will Deacon <will@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Ian Rogers <irogers@google.com> Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21ring-buffer: Fix reporting of missed events in iteratorSteven Rostedt
When tracing is active while reading the trace file, if the iterator reading the buffer detects that the writer has passed the iterator head, it will reset and set a "missed events" flag. This flag is passed to the output processing to show the user that events were missed: CPU:4 [LOST EVENTS] The problem is that the flag is reset after it is checked in ring_buffer_iter_dropped(). But the "trace" file iterates over all the CPU ring buffers and it will check if they are dropped when figuring out which buffer to print next. This prematurely clears the missed_events flag if the CPU buffer with the missed events is not the one that is printed next. On the iteration where the CPU buffer with the missed events is printed, the check if it had missed events would return false and the output does not show that events were missed. Do not reset the missed_events flag when checking if there were missed events, but instead clear it when moving the iterator head to the next event. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20260520220801.4fd09d13@fedora Fixes: c9b7a4a72ff64 ("ring-buffer/tracing: Have iterator acknowledge dropped events") Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-20tracing: Avoid NULL return from hist_field_name() on truncationDavid Carlier
hist_field_name() returns "" everywhere except the fully-qualified VAR_REF/EXPR case, where snprintf() truncation returns NULL early and bypasses the bottom NULL->"" guard. Callers don't expect NULL: strcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758 and the strcmp() in the sort-key match loop at :4804 both deref it. system and event_name are bounded by MAX_EVENT_NAME_LEN, but the field name on a VAR_REF is kstrdup'd from a histogram variable name parsed out of the trigger string and has no length cap, so a long enough var name in a fully qualified reference can reach the truncation path. Keep the length check but leave field_name as "" on overflow. Link: https://patch.msgid.link/20260508195747.25492-1-devnexen@gmail.com Fixes: 5ec1d1e97de1 ("tracing: Rebuild full_name on each hist_field_name() call") Signed-off-by: David Carlier <devnexen@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-17Merge tag 'trace-v7.1-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Add more functions to the remote allowed list randconfig found more functions that are allowed for the remote code for s390 and arm. Add them to the allowed list. - Fix remote_test error path If one of the simple ring buffers fails to load, the code is supposed to rollback its initialized buffers. Instead of rolling back the buffers for the failed load, it uses the global variable and rolls back all the successfully loaded buffers. * tag 'trace-v7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Fix desc in error path for the trace remote test module ring-buffer remote: Avoid unexpected symbol warnings (arm, s390)
2026-05-16tracing: Fix desc in error path for the trace remote test moduleVincent Donnefort
During initialisation in remote_test_load(), if one of the simple_ring_buffer fails to initialise, the error path attempts to rollback initialised buffers. However, the rollback incorrectly uses the global pointer to the trace descriptor, which is only set upon successful load completion. Fix the error path by using the local pointer to the descriptor. Link: https://patch.msgid.link/20260515201616.337469-1-vdonnefort@google.com Fixes: ea908a2b79c8 ("tracing: Add a trace remote module for testing") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> base-commit: 5d6919055dec134de3c40167a490f33c74c12581 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-15ring-buffer remote: Avoid unexpected symbol warnings (arm, s390)Arnd Bergmann
The now more verbose check found more architecture specific symbol missing from the whitelist, during randconfig testing on s390 and 32-bit arm: Unexpected symbols in kernel/trace/simple_ring_buffer.o: U __aeabi_unwind_cpp_pr1 Unexpected symbols in kernel/trace/simple_ring_buffer.o: U __s390_indirect_jump_r1 U __s390_indirect_jump_r10 U __s390_indirect_jump_r14 U __s390_indirect_jump_r2 U __s390_indirect_jump_r5 U __s390_indirect_jump_r7 U __s390_indirect_jump_r8 U __s390_indirect_jump_r9 make[6]: *** [/home/arnd/arm-soc/kernel/trace/Makefile:160: kernel/trace/simple_ring_buffer.o.checked] Error 1 Add these to the list and keep it roughly sorted into sanitizer and architecture symbols. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: https://patch.msgid.link/20260515105717.1023007-1-arnd@kernel.org Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-11fprobe: Fix unregister_fprobe() to wait for RCU grace periodMasami Hiramatsu (Google)
Commit 4346ba1604093 ("fprobe: Rewrite fprobe on function-graph tracer") changed fprobe to register struct fprobe to an rcu-hlist, but it forgot to wait for RCU GP. Thus there can be use-after-free if the fprobe is released right after unregistering. This can be happened on fprobe event and sample module code. To fix this issue, add synchronize_rcu() in unregister_fprobe(). Note that BPF is OK because fprobe is used as a part of bpf_kprobe_multi_link. This unregisters its fprobe in bpf_kprobe_multi_link_release() and it is deallocated via bpf_kprobe_multi_link_dealloc(), which is invoked from bpf_link_defer_dealloc_rcu_gp() RCU callback. For BPF, this also introduced unregister_fprobe_async() which does NOT wait for RCU grace priod. Link: https://lore.kernel.org/all/177813998919.256460.2809243930741138224.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba1604093 ("fprobe: Rewrite fprobe on function-graph tracer") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-29tracing/probes: Limit size of event probe to 3KSteven Rostedt
There currently isn't a max limit an event probe can be. One could make an event greater than PAGE_SIZE, which makes the event useless because if it's bigger than the max event that can be recorded into the ring buffer, then it will never be recorded. A event probe should never need to be greater than 3K, so make that the max size. As long as the max is less than the max that can be recorded onto the ring buffer, it should be fine. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events") Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-04-28tracing: branch: Fix inverted check on stat tracer registrationBreno Leitao
init_annotated_branch_stats() and all_annotated_branch_stats() check the return value of register_stat_tracer() with "if (!ret)", but register_stat_tracer() returns 0 on success and a negative errno on failure. The inverted check causes the warning to be printed on every successful registration, e.g.: Warning: could not register annotated branches stats while leaving real failures silent. The initcall also returned a hard-coded 1 instead of the actual error. Invert the check and propagate ret so that the warning fires on real errors and the initcall reports the correct status. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: https://patch.msgid.link/20260420-tracing-v1-1-d8f4cd0d6af1@debian.org Fixes: 002bb86d8d42 ("tracing/ftrace: separate events tracing and stats tracing engine") Signed-off-by: Breno Leitao <leitao@debian.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-04-24Merge tag 'trace-ring-buffer-v7.1-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ring-buffer fix from Steven Rostedt: - Fix accounting of persistent ring buffer rewind On boot up, the head page is moved back to the earliest point of the saved ring buffer. This is because the ring buffer being read by user space on a crash may not save the part it read. Rewinding the head page back to the earliest saved position helps keep those events from being lost. The number of events is also read during boot up and displayed in the stats file in the tracefs directory. It's also used for other accounting as well. On boot up, the "reader page" is accounted for but a rewind may put it back into the buffer and then the reader page may be accounted for again. Save off the original reader page and skip accounting it when scanning the pages in the ring buffer. * tag 'trace-ring-buffer-v7.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Do not double count the reader_page
2026-04-24ring-buffer: Do not double count the reader_pageMasami Hiramatsu (Google)
Since the cpu_buffer->reader_page is updated if there are unwound pages. After that update, we should skip the page if it is the original reader_page, because the original reader_page is already checked. Cc: stable@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Ian Rogers <irogers@google.com> Link: https://patch.msgid.link/177701353063.2223789.1471163147644103306.stgit@mhiramat.tok.corp.google.com Fixes: ca296d32ece3 ("tracing: ring_buffer: Rewind persistent ring buffer on reboot") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-04-22Merge tag 'trace-ring-buffer-v7.1-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ring-buffer fix from Steven Rostedt: - Make undefsyms_base.c into a real file The file undefsyms_base.c is used to catch any symbols used by a remote ring buffer that is made for use of a pKVM hypervisor. As it doesn't share the same text as the rest of the kernel, referencing any symbols within the kernel will make it fail to be built for the standalone hypervisor. A file was created by the Makefile that checked for any symbols that could cause issues. There's no reason to have this file created by the Makefile, just create it as a normal file instead. * tag 'trace-ring-buffer-v7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Make undefsyms_base.c a first-class citizen
2026-04-22tracing: Make undefsyms_base.c a first-class citizenPaolo Bonzini
Linus points out that dumping undefsyms_base.c form the Makefile is rather ugly, and that a much better course of action would be to have this file as a first-class citizen in the git tree. This allows some extra cleanup in the Makefile, and the removal of the .gitignore file in kernel/trace. Cc: Marc Zyngier <maz@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/CAHk-=wieqGd_XKpu8UxDoyADZx8TDe8CF3RmkUXt5N_9t5Pf_w@mail.gmail.com Link: https://lore.kernel.org/all/20260421095446.2951646-1-maz@kernel.org/ Link: https://patch.msgid.link/20260421100455.324333-1-pbonzini@redhat.com Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-04-22tracing/fprobe: Fix to unregister ftrace_ops if it is empty on module unloadingMasami Hiramatsu (Google)
Fix fprobe to unregister ftrace_ops if corresponding type of fprobe does not exist on the fprobe_ip_table and it is expected to be empty when unloading modules. Since ftrace thinks that the empty hash means everything to be traced, if we set fprobes only on the unloaded module, all functions are traced unexpectedly after unloading module. e.g. # modprobe xt_LOG.ko # echo 'f:test log_tg*' > dynamic_events # echo 1 > events/fprobes/test/enable # cat enabled_functions log_tg [xt_LOG] (1) tramp: 0xffffffffa0004000 (fprobe_ftrace_entry+0x0/0x490) ->fprobe_ftrace_entry+0x0/0x490 log_tg_check [xt_LOG] (1) tramp: 0xffffffffa0004000 (fprobe_ftrace_entry+0x0/0x490) ->fprobe_ftrace_entry+0x0/0x490 log_tg_destroy [xt_LOG] (1) tramp: 0xffffffffa0004000 (fprobe_ftrace_entry+0x0/0x490) ->fprobe_ftrace_entry+0x0/0x490 # rmmod xt_LOG # wc -l enabled_functions 34085 enabled_functions Link: https://lore.kernel.org/all/177669368776.132053.10042301916765771279.stgit@mhiramat.tok.corp.google.com/ Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-22tracing/fprobe: Check the same type fprobe on table as the unregistered oneMasami Hiramatsu (Google)
Commit 2c67dc457bc6 ("tracing: fprobe: optimization for entry only case") introduced a different ftrace_ops for entry-only fprobes. However, when unregistering an fprobe, the kernel only checks if another fprobe exists at the same address, without checking which type of fprobe it is. If different fprobes are registered at the same address, the same address will be registered in both fgraph_ops and ftrace_ops, but only one of them will be deleted when unregistering. (the one removed first will not be deleted from the ops). This results in junk entries remaining in either fgraph_ops or ftrace_ops. For example: ======= cd /sys/kernel/tracing # 'Add entry and exit events on the same place' echo 'f:event1 vfs_read' >> dynamic_events echo 'f:event2 vfs_read%return' >> dynamic_events # 'Enable both of them' echo 1 > events/fprobes/enable cat enabled_functions vfs_read (2) ->arch_ftrace_ops_list_func+0x0/0x210 # 'Disable and remove exit event' echo 0 > events/fprobes/event2/enable echo -:event2 >> dynamic_events # 'Disable and remove all events' echo 0 > events/fprobes/enable echo > dynamic_events # 'Add another event' echo 'f:event3 vfs_open%return' > dynamic_events cat dynamic_events f:fprobes/event3 vfs_open%return echo 1 > events/fprobes/enable cat enabled_functions vfs_open (1) tramp: 0xffffffffa0001000 (ftrace_graph_func+0x0/0x60) ->ftrace_graph_func+0x0/0x60 subops: {ent:fprobe_fgraph_entry+0x0/0x620 ret:fprobe_return+0x0/0x150} vfs_read (1) tramp: 0xffffffffa0001000 (ftrace_graph_func+0x0/0x60) ->ftrace_graph_func+0x0/0x60 subops: {ent:fprobe_fgraph_entry+0x0/0x620 ret:fprobe_return+0x0/0x150} ======= As you can see, an entry for the vfs_read remains. To fix this issue, when unregistering, the kernel should also check if there is the same type of fprobes still exist at the same address, and if not, delete its entry from either fgraph_ops or ftrace_ops. Link: https://lore.kernel.org/all/177669367993.132053.10553046138528674802.stgit@mhiramat.tok.corp.google.com/ Fixes: 2c67dc457bc6 ("tracing: fprobe: optimization for entry only case") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-22tracing/fprobe: Avoid kcalloc() in rcu_read_lock sectionMasami Hiramatsu (Google)
fprobe_remove_node_in_module() is called under RCU read locked, but this invokes kcalloc() if there are more than 8 fprobes installed on the module. Sashiko warns it because kcalloc() can sleep [1]. [1] https://sashiko.dev/#/patchset/177552432201.853249.5125045538812833325.stgit%40mhiramat.tok.corp.google.com To fix this issue, expand the batch size to 128 and do not expand the fprobe_addr_list, but just cancel walking on fprobe_ip_table, update fgraph/ftrace_ops and retry the loop again. Link: https://lore.kernel.org/all/177669367206.132053.1493637946869032744.stgit@mhiramat.tok.corp.google.com/ Fixes: 0de4c70d04a4 ("tracing: fprobe: use rhltable for fprobe_ip_table") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-21tracing/fprobe: Remove fprobe from hash in failure pathMasami Hiramatsu (Google)
When register_fprobe_ips() fails, it tries to remove a list of fprobe_hash_node from fprobe_ip_table, but it missed to remove fprobe itself from fprobe_table. Moreover, when removing the fprobe_hash_node which is added to rhltable once, it must use kfree_rcu() after removing from rhltable. To fix these issues, this reuses unregister_fprobe() internal code to rollback the half-way registered fprobe. Link: https://lore.kernel.org/all/177669366417.132053.17874946321744910456.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-21tracing/fprobe: Unregister fprobe even if memory allocation failsMasami Hiramatsu (Google)
unregister_fprobe() can fail under memory pressure because of memory allocation failure, but this maybe called from module unloading, and usually there is no way to retry it. Moreover. trace_fprobe does not check the return value. To fix this problem, unregister fprobe and fprobe_hash_node even if working memory allocation fails. Anyway, if the last fprobe is removed, the filter will be freed. Link: https://lore.kernel.org/all/177669365629.132053.8433032896213721288.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-21tracing/fprobe: Reject registration of a registered fprobe before initMasami Hiramatsu (Google)
Reject registration of a registered fprobe which is on the fprobe hash table before initializing fprobe. The add_fprobe_hash() checks this re-register fprobe, but since fprobe_init() clears hlist_array field, it is too late to check it. It has to check the re-registration before touncing fprobe. Link: https://lore.kernel.org/all/177669364845.132053.18375367916162315835.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2026-04-20tracing: tell git to ignore the generated 'undefsyms_base.c' fileLinus Torvalds
This odd file was added to automatically figure out tool-generated symbols. Honestly, it *should* have been just a real honest-to-goodness regular file in git, instead of having strange code to generate it in the Makefile, but that is not how that silly thing works. So now we need to ignore it explicitly. Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer") Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-04-17Merge tag 'trace-latency-v7.1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing latency update from Steven Rostedt: - Add TIMERLAT_ALIGN osnoise option Add a timer alignment option for timerlat that makes it work like the cyclictest -A option. timelat creates threads to test the latency of the kernel. The alignment option will have these threads trigger at the alignment offsets from each other. Instead of having each thread wake up at the exact same time, if the alignment is set to "20" each thread will wake up at 20 microseconds from the previous one. * tag 'trace-latency-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/osnoise: Add option to align tlat threads
generated by cgit v1.2.3 (git 2.25.1) at 2026-08-03 05:08:57 +0000