Krystian Kaniewski 89bab1dba8 ring-buffer: Fix false warning in ring_buffer_map_get_reader() ... The mmap reader can warn when it catches up with a writer that is still committing events. rb_get_reader_page() returns NULL in this case, but ring_buffer_map_get_reader() treats that result as an error. The initial rb_per_cpu_empty() check filters out an empty buffer, but it does not guarantee that the next reader page has committed data. Writers do not take reader_lock and can advance commit_page before publishing the committed length on the new page. rb_get_reader_page() can swap to that page, catch up with the writer and return NULL. Handle NULL through the existing no-data exit without warning. Remove the caller's reader_page == commit_page check as well, since the reader-page helper already handles that case. The existing metadata update and return path remain in place. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260924084946.20104-1-krystianmkaniewski@gmail.com Fixes: 117c39200d ("ring-buffer: Introducing ring-buffer mapping functions") Assisted-by: Gemini:gemini-3.8-flash syzbot Reported-by: syzbot+de3d7f9bcc9212f3fae1@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=de3d7f9bcc9212f3fae1 Link: https://syzkaller.appspot.com/ai_job?id=488adc18-a10e-42d2-a205-25327c38837f Signed-off-by: Krystian Kaniewski <krystianmkaniewski@gmail.com> Reviewed-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2026-10-14 19:03:39 -04:00
..
rv	rv: Fix 32-bit build of nomiss KUnit test	2026-08-04 16:11:27 +02:00
blktrace.c
bpf_trace.c	bpf: Make bpf_trampoline_multi_detach return void	2026-08-13 02:52:23 +02:00
bpf_trace.h
error_report-traces.c
fgraph.c	fgraph: Remove unused FGRAPH_MAX_INDEX	2026-09-11 13:37:50 -04:00
fprobe.c	fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching()	2026-09-30 08:41:31 +09:00
ftrace_internal.h
ftrace.c	ftrace: Use rcu_assign_pointer() for tmp_ops filter hash	2026-09-12 13:27:29 -04:00
Kconfig	tracing/probes: Support dumping fetcharg program for debugging dynamic events	2026-07-02 21:12:40 +09:00
kprobe_event_gen_test.c
Makefile	tracing: Fix simple_ring_buffer undef check on sparc64	2026-10-14 19:03:39 -04:00
pid_list.c
pid_list.h
power-traces.c
preemptirq_delay_test.c	tracing: Reject invalid preemptirq_delay_test CPU affinity	2026-07-28 07:18:50 -04:00
remote_test_events.h	tracing: Add a trace remote module for testing	2026-03-09 12:33:55 -04:00
remote_test.c	tracing: Fix desc in error path for the trace remote test module	2026-05-16 16:11:04 -04:00
rethook.c	tracing: Fix typo "availabe" in comment	2026-09-11 13:54:14 -04:00
ring_buffer_benchmark.c	tracing: Fix subbuf resize races with trace_pipe_raw readers	2026-09-04 16:19:07 -04:00
ring_buffer.c	ring-buffer: Fix false warning in ring_buffer_map_get_reader()	2026-10-14 19:03:39 -04:00
rpm-traces.c
simple_ring_buffer.c	tracing: Fix retry exhaustion in simple ring buffer reader swap	2026-08-27 21:31:41 -04:00
synth_event_gen_test.c
trace_benchmark.c
trace_benchmark.h
trace_boot.c	tracing/boot: Add support for eprobe, fprobe, and tprobe events	2026-08-08 21:20:55 +09:00
trace_branch.c	tracing/branch: Use pr_warn() instead of printk(KERN_WARNING)	2026-05-21 18:03:08 -04:00
trace_btf.c	tracing/probes: Fix BTF kflag check for anonymous struct member access	2026-09-03 09:04:25 +09:00
trace_btf.h	tracing/probes: Fix BTF kflag check for anonymous struct member access	2026-09-03 09:04:25 +09:00
trace_clock.c
trace_dynevent.c	tracing/boot: Add support for eprobe, fprobe, and tprobe events	2026-08-08 21:20:55 +09:00
trace_dynevent.h
trace_entries.h
trace_eprobe.c	treewide: refresh kmalloc_obj() conversions	2026-09-04 21:37:00 -07:00
trace_event_perf.c	perf/ftrace: Fix WARNING in __unregister_ftrace_function	2026-05-29 11:27:40 -04:00
trace_events_filter_test.h
trace_events_filter.c	tracing/filters: Fix false positive match in regex_match_full()	2026-07-29 14:32:11 -04:00
trace_events_hist.c	tracing: Fix the shift out of bounds in the log2 histogram modifier	2026-10-14 17:47:24 -04:00
trace_events_inject.c
trace_events_synth.c	tracing/synthetic: Free type string on error path	2026-07-07 13:59:55 -04:00
trace_events_trigger.c	tracing: Don't dereference trace_event_file in deferred trigger free	2026-09-12 13:27:41 -04:00
trace_events_user.c	tracing/user_events: Don't destroy fields when event removal fails	2026-09-11 13:30:15 -04:00
trace_events.c	tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()	2026-09-11 14:01:46 -04:00
trace_export.c
trace_fprobe.c	Probes updates for v7.3:	2026-08-20 15:11:52 -07:00
trace_functions_graph.c	function_graph: Use the saved entry's size when reprinting it	2026-09-11 13:39:08 -04:00
trace_functions.c	ftrace: Take trace_array reference before accessing its ftrace_ops	2026-09-01 16:38:19 -04:00
trace_hwlat.c
trace_irqsoff.c
trace_kdb.c
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c	tracing/probes: Treating longer symbol name on event comparation	2026-07-28 23:55:35 +09:00
trace_mmiotrace.c	tracing updates for v7.3:	2026-08-19 14:06:14 -07:00
trace_nop.c
trace_osnoise.c	tracing/osnoise: Call synchronize_rcu() when unregistering	2026-07-06 14:56:18 -04:00
trace_output.c	tracing updates for v7.1:	2026-04-17 09:43:12 -07:00
trace_output.h
trace_pid.c
trace_preemptirq.c	tracing: Add a no-rcu-check version of trace_##event##_enabled()	2026-07-07 10:42:29 -04:00
trace_printk.c	kernel/trace/trace_printk: Use kstrdup() instead of kmalloc() and strcpy()	2026-07-28 07:18:48 -04:00
trace_probe_kernel.h	tracing/probes: Fix extra whitespace in trace_probe_kernel.h	2026-07-21 18:00:13 +09:00
trace_probe_tmpl.h	tracing/probes: Add this_cpu_read() and this_cpu_ptr() dereference method to fetcharg	2026-07-14 22:43:16 +09:00
trace_probe.c	tracing/probes: Fix use-after-free on field name/type of events with multiple probes	2026-09-03 09:04:25 +09:00
trace_probe.h	tracing/probes: Fix use-after-free on field name/type of events with multiple probes	2026-09-03 09:04:25 +09:00
trace_recursion_record.c	tracing: Switch trace_recursion_record.c code over to use guard()	2026-05-21 18:03:07 -04:00
trace_remote.c	tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing	2026-09-13 13:06:43 -04:00
trace_sched_switch.c	tracing: Use strscpy() instead of strcpy() in trace_sched_switch	2026-07-28 07:18:50 -04:00
trace_sched_wakeup.c
trace_selftest_dynamic.c
trace_selftest.c
trace_seq.c
trace_snapshot.c	tracing: Remove duplicate latency_fsnotify() stub	2026-03-31 14:58:39 -04:00
trace_stack.c	ftrace: Take trace_array reference before accessing its ftrace_ops	2026-09-01 16:38:19 -04:00
trace_stat.c
trace_stat.h
trace_synth.h
trace_syscalls.c	tracing: Make per-template BTF id lists file-local	2026-08-05 22:02:29 -04:00
trace_uprobe.c	uprobes: guard trace cleanup against error pointers	2026-09-01 09:50:11 +09:00
trace.c	tracing: Take trace_types_lock when dropping the buffer_meta reference	2026-10-14 17:47:24 -04:00
trace.h	tracing: Don't dereference trace_event_file in deferred trigger free	2026-09-12 13:27:41 -04:00
tracing_map.c	tracing: Simplify pages allocation for tracing_map logic	2026-05-21 18:12:10 -04:00
tracing_map.h	tracing: Simplify pages allocation for tracing_map logic	2026-05-21 18:12:10 -04:00
undefsyms_base.c	tracing: Fix simple_ring_buffer undef check on parisc	2026-10-14 19:03:39 -04:00