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The persistent ring buffer from a previous boot has to be careful printing events as the print formats of random events can have pointers to strings and such that are not available. Ftrace static events (like the function tracer event) are stable and are printed normally. System call event formats are also stable. Allow them to be printed normally as well: Instead of: <...>-1 [005] ...1. 57.240405: sys_enter_waitid: __syscall_nr=0xf7 (247) which=0x1 (1) upid=0x499 (1177) infop=0x7ffd5294d690 (140725988939408) options=0x5 (5) ru=0x0 (0) <...>-1 [005] ...1. 57.240433: sys_exit_waitid: __syscall_nr=0xf7 (247) ret=0x0 (0) <...>-1 [005] ...1. 57.240437: sys_enter_rt_sigprocmask: __syscall_nr=0xe (14) how=0x2 (2) nset=0x7ffd5294d7c0 (140725988939712) oset=0x0 (0) sigsetsize=0x8 (8) <...>-1 [005] ...1. 57.240438: sys_exit_rt_sigprocmask: __syscall_nr=0xe (14) ret=0x0 (0) <...>-1 [005] ...1. 57.240442: sys_enter_close: __syscall_nr=0x3 (3) fd=0x4 (4) <...>-1 [005] ...1. 57.240463: sys_exit_close: __syscall_nr=0x3 (3) ret=0x0 (0) <...>-1 [005] ...1. 57.240485: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param <...>-1 [005] ...1. 57.240555: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154) <...>-1 [005] ...1. 57.240571: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param <...>-1 [005] ...1. 57.240620: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154) <...>-1 [005] ...1. 57.240629: sys_enter_writev: __syscall_nr=0x14 (20) fd=0x3 (3) vec=0x7ffd5294ce50 (140725988937296) vlen=0x7 (7) <...>-1 [005] ...1. 57.242281: sys_exit_writev: __syscall_nr=0x14 (20) ret=0x24 (36) <...>-1 [005] ...1. 57.242286: sys_enter_reboot: __syscall_nr=0xa9 (169) magic1=0xfee1dead (4276215469) magic2=0x28121969 (672274793) cmd=0x1234567 (19088743) arg=0x0 (0) Have: <...>-1 [000] ...1. 91.446011: sys_waitid(which: 1, upid: 0x4d2, infop: 0x7ffdccdadfd0, options: 5, ru: 0) <...>-1 [000] ...1. 91.446042: sys_waitid -> 0x0 <...>-1 [000] ...1. 91.446045: sys_rt_sigprocmask(how: 2, nset: 0x7ffdccdae100, oset: 0, sigsetsize: 8) <...>-1 [000] ...1. 91.446047: sys_rt_sigprocmask -> 0x0 <...>-1 [000] ...1. 91.446051: sys_close(fd: 4) <...>-1 [000] ...1. 91.446073: sys_close -> 0x0 <...>-1 [000] ...1. 91.446095: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC) <...>-1 [000] ...1. 91.446165: sys_openat -> 0xfffffffffffffffe <...>-1 [000] ...1. 91.446182: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC) <...>-1 [000] ...1. 91.446233: sys_openat -> 0xfffffffffffffffe <...>-1 [000] ...1. 91.446242: sys_writev(fd: 3, vec: 0x7ffdccdad790, vlen: 7) <...>-1 [000] ...1. 91.447877: sys_writev -> 0x24 <...>-1 [000] ...1. 91.447883: sys_reboot(magic1: 0xfee1dead, magic2: 0x28121969, cmd: 0x1234567, arg: 0) 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> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Takaya Saeki <takayas@google.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ian Rogers <irogers@google.com> Cc: Douglas Raillard <douglas.raillard@arm.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Link: https://lore.kernel.org/20251028231149.097404581@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>