linux/kernel/trace
Arnd Bergmann 7e1f4eb9a6 kallsyms: rework symbol lookup return codes
Building with W=1 in some configurations produces a false positive
warning for kallsyms:

kernel/kallsyms.c: In function '__sprint_symbol.isra':
kernel/kallsyms.c:503:17: error: 'strcpy' source argument is the same as destination [-Werror=restrict]
  503 |                 strcpy(buffer, name);
      |                 ^~~~~~~~~~~~~~~~~~~~

This originally showed up while building with -O3, but later started
happening in other configurations as well, depending on inlining
decisions. The underlying issue is that the local 'name' variable is
always initialized to the be the same as 'buffer' in the called functions
that fill the buffer, which gcc notices while inlining, though it could
see that the address check always skips the copy.

The calling conventions here are rather unusual, as all of the internal
lookup functions (bpf_address_lookup, ftrace_mod_address_lookup,
ftrace_func_address_lookup, module_address_lookup and
kallsyms_lookup_buildid) already use the provided buffer and either return
the address of that buffer to indicate success, or NULL for failure,
but the callers are written to also expect an arbitrary other buffer
to be returned.

Rework the calling conventions to return the length of the filled buffer
instead of its address, which is simpler and easier to follow as well
as avoiding the warning. Leave only the kallsyms_lookup() calling conventions
unchanged, since that is called from 16 different functions and
adapting this would be a much bigger change.

Link: https://lore.kernel.org/lkml/20200107214042.855757-1-arnd@arndb.de/
Link: https://lore.kernel.org/lkml/20240326130647.7bfb1d92@gandalf.local.home/
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-06-27 17:43:40 +02:00
..
rv rv: Update rv_en(dis)able_monitor doc to match kernel-doc 2024-05-21 19:03:35 -04:00
blktrace.c blktrace: convert strncpy() to strscpy_pad() 2024-04-25 21:07:08 -07:00
bpf_trace.c bpf: Fix bpf_session_cookie BTF_ID in special_kfunc_set list 2024-05-31 14:54:48 -07:00
bpf_trace.h tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
error_report-traces.c
fgraph.c ftrace: Remove unused global 'ftrace_direct_func_count' 2024-05-14 02:09:40 -04:00
fprobe.c fprobe: Fix to allocate entry_data_size buffer with rethook instances 2024-03-01 09:18:24 +09:00
ftrace_internal.h
ftrace.c kallsyms: rework symbol lookup return codes 2024-06-27 17:43:40 +02:00
Kconfig tracing: Build event generation tests only as modules 2024-06-12 08:43:12 +09:00
kprobe_event_gen_test.c
Makefile tracing/probes: Move finding func-proto API and getting func-param API to trace_btf 2023-08-23 09:39:45 +09:00
pid_list.c
pid_list.h
power-traces.c
preemptirq_delay_test.c tracing: Add MODULE_DESCRIPTION() to preemptirq_delay_test 2024-05-21 19:03:35 -04:00
rethook.c rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get() 2024-05-01 23:18:48 +09:00
ring_buffer_benchmark.c ring-buffer: Read and write to ring buffers with custom sub buffer size 2023-12-20 07:54:56 -05:00
ring_buffer.c ring-buffer: Fix a race between readers and resize checks 2024-05-21 19:03:35 -04:00
rpm-traces.c
synth_event_gen_test.c tracing / synthetic: Disable events after testing in synth_event_gen_test_init() 2023-12-21 10:04:45 -05:00
trace_benchmark.c tracing: Improve benchmark test performance by using do_div() 2024-05-13 20:00:57 -04:00
trace_benchmark.h
trace_boot.c tracing: Allow creating instances with specified system events 2023-12-18 23:14:16 -05:00
trace_branch.c
trace_btf.c tracing/probes: Fix to search structure fields correctly 2024-02-17 21:25:42 +09:00
trace_btf.h tracing/probes: Add a function to search a member of a struct/union 2023-08-23 09:40:16 +09:00
trace_clock.c
trace_dynevent.c
trace_dynevent.h
trace_entries.h tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure 2023-07-30 18:11:44 -04:00
trace_eprobe.c tracing/probes: Support $argN in return probe (kprobe and fprobe) 2024-03-07 00:27:34 +09:00
trace_event_perf.c
trace_events_filter_test.h
trace_events_filter.c tracing: Have trace_event_file have ref counters 2023-11-01 23:44:44 -04:00
trace_events_hist.c tracing histograms: Simplify parse_actions() function 2024-01-08 13:24:56 -05:00
trace_events_inject.c tracing: Have event inject files inc the trace array ref count 2023-09-07 16:38:54 -04:00
trace_events_synth.c tracing/synthetic: Fix trace_string() return value 2024-02-15 11:40:01 -05:00
trace_events_trigger.c tracing: Decrement the snapshot if the snapshot trigger fails to register 2024-03-18 10:33:05 -04:00
trace_events_user.c user-event updates for v6.10: 2024-05-17 18:46:30 -07:00
trace_events.c eventfs/tracing: Add callback for release of an eventfs_inode 2024-05-04 04:25:37 -04:00
trace_export.c tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure 2023-07-30 18:11:44 -04:00
trace_fprobe.c tracing/probes: support '%pd' type for print struct dentry's name 2024-05-01 23:18:47 +09:00
trace_functions_graph.c
trace_functions.c
trace_hwlat.c tracing: Remove extra space at the end of hwlat_detector/mode 2023-09-01 21:00:00 -04:00
trace_irqsoff.c tracing: Fix memleak due to race between current_tracer and trace 2023-08-17 13:49:37 -04:00
trace_kdb.c
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c Probes updates for v6.10: 2024-05-17 18:29:30 -07:00
trace_mmiotrace.c
trace_nop.c
trace_osnoise.c tracing/timerlat: Move hrtimer_init to timerlat_fd open() 2024-02-01 11:50:13 -05:00
trace_output.c tracing: Remove precision vsnprintf() check from print event 2024-03-06 13:26:26 -05:00
trace_output.h
trace_preemptirq.c
trace_printk.c
trace_probe_kernel.h
trace_probe_tmpl.h tracing/probes: Support $argN in return probe (kprobe and fprobe) 2024-03-07 00:27:34 +09:00
trace_probe.c tracing/probes: fix error check in parse_btf_field() 2024-05-27 21:32:35 +09:00
trace_probe.h tracing/probes: support '%pd' type for print struct dentry's name 2024-05-01 23:18:47 +09:00
trace_recursion_record.c
trace_sched_switch.c tracing: Move saved_cmdline code into trace_sched_switch.c 2024-03-17 07:58:53 -04:00
trace_sched_wakeup.c tracing: Fix memleak due to race between current_tracer and trace 2023-08-17 13:49:37 -04:00
trace_selftest_dynamic.c
trace_selftest.c tracing: Support to dump instance traces by ftrace_dump_on_oops 2024-03-18 10:33:06 -04:00
trace_seq.c trace_seq: Increase the buffer size to almost two pages 2023-12-18 23:14:16 -05:00
trace_stack.c
trace_stat.c
trace_stat.h
trace_synth.h
trace_syscalls.c bpf: Change syscall_nr type to int in struct syscall_tp_t 2023-10-13 12:39:36 -07:00
trace_uprobe.c uprobes: prevent mutex_lock() under rcu_read_lock() 2024-05-24 07:44:44 +09:00
trace.c tracing ring buffer updates for v6.10: 2024-05-17 18:40:37 -07:00
trace.h tracing: Allow user-space mapping of the ring-buffer 2024-05-13 18:09:56 -04:00
tracing_map.c tracing: Ensure visibility when inserting an element into tracing_map 2024-01-22 17:15:40 -05:00
tracing_map.h