[Crash-utility] Re: [PATCH v2 3/3] Enable resolving mangled Rust symbol in lockless ring buffer

Hi lianbo, Thanks for the v2, LGTM, ack. On Mon, Sep 8, 2025 at 8:42 PM Lianbo Jiang <lijiang(a)redhat.com&gt; wrote: > > Without the patch: > crash> log > ... > [ 2174.308966] Call Trace: > [ 2174.311693] <TASK> > [ 2174.314033] dump_stack_lvl+0x5d/0x80 > [ 2174.318125] panic+0x156/0x32a > [ 2174.321539] _RNvCscb18lrEyTSA_10rust_panic10area_in_hp+0xf7/0x120 [rust_panic] > [ 2174.329700] ? console_unlock+0x9c/0x140 > [ 2174.334080] ? irq_work_queue+0x2d/0x50 > [ 2174.338352] ? __pfx_init_module+0x10/0x10 [rust_panic] > [ 2174.344183] _RNvMCscb18lrEyTSA_10rust_panicNtB2_10HelloPanic8step_two+0x20/0xe0 [rust_panic] > [ 2174.353698] ? _printk+0x6b/0x90 > ... > > With the patch: > crash> log > ... > [ 2174.308966] Call Trace: > [ 2174.311693] <TASK> > [ 2174.314033] dump_stack_lvl+0x5d/0x80 > [ 2174.318125] panic+0x156/0x32a > [ 2174.321539] rust_panic::area_in_hp+0xf7/0x120 [rust_panic] > [ 2174.329700] ? console_unlock+0x9c/0x140 > [ 2174.334080] ? irq_work_queue+0x2d/0x50 > [ 2174.338352] ? __pfx_init_module+0x10/0x10 [rust_panic] > [ 2174.344183] <rust_panic::HelloPanic>::step_two+0x20/0xe0 [rust_panic] > [ 2174.353698] ? _printk+0x6b/0x90 > ... > > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; > --- > Note: > 1. Add some checks to avoid the risk of buffer overflow. > > Makefile | 2 +- > printk.c | 33 ++++++++++++++++++++++++++++++++- > 2 files changed, 33 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index fc1c9588dcfa..b277129f6df2 100644 > --- a/Makefile > +++ b/Makefile > @@ -421,7 +421,7 @@ kernel.o: ${GENERIC_HFILES} kernel.c > ${CC} -c ${CRASH_CFLAGS} kernel.c -I${BFD_DIRECTORY} -I${GDB_INCLUDE_DIRECTORY} ${WARNING_OPTIONS} ${WARNING_ERROR} > > printk.o: ${GENERIC_HFILES} printk.c > - ${CC} -c ${CRASH_CFLAGS} printk.c ${WARNING_OPTIONS} ${WARNING_ERROR} > + ${CC} -c ${CRASH_CFLAGS} printk.c -I${GDB_INCLUDE_DIRECTORY} ${WARNING_OPTIONS} ${WARNING_ERROR} > > gdb_interface.o: ${GENERIC_HFILES} gdb_interface.c > ${CC} -c ${CRASH_CFLAGS} gdb_interface.c ${WARNING_OPTIONS} ${WARNING_ERROR} > diff --git a/printk.c b/printk.c > index 95db7e607e4c..ae28c4fa0b21 100644 > --- a/printk.c > +++ b/printk.c > @@ -1,5 +1,6 @@ > #include "defs.h" > #include <ctype.h> > +#include "demangle.h" > > /* convenience struct for passing many values to helper functions */ > struct prb_map { > @@ -201,14 +202,44 @@ dump_record(struct prb_map *m, unsigned long id, int msg_flags) > > text = m->text_data + begin; > > + if (text_len > BUFSIZE) { > + error(WARNING, "\nThe messages could be truncated!\n"); > + text_len = BUFSIZE; > + } > + > for (i = 0, p = text; i < text_len; i++, p++) { > if (*p == '\n') > fprintf(fp, "\n%s", space(ilen)); > else if (isprint(*p) || isspace(*p)) > - fputc(*p, fp); > + sprintf(&buf[i], "%c", *p); > else > fputc('.', fp); > } > + /* > + * Try to demangle a mangled Rust symbol(calltrace) from log buffer > + */ > + char *p1 = strstr(buf, "_R"); > + if (!p1) > + p1 = strstr(buf, "_ZN"); > + char *p2 = strchrnul(buf, '+'); > + if (p1 && p2) { > + char mangled[BUFSIZE] = {0}; > + char demangled[BUFSIZE] = {0}; > + char *res; > + size_t slen = p1 - buf; > + > + if (slen) > + memcpy(demangled, buf, slen); > + > + memcpy(mangled, p1, p2-p1); > + res = rust_demangle(mangled, DMGL_RUST); > + if (res) { > + snprintf(demangled+slen, BUFSIZE-slen, "%s%s", res, p2); > + fprintf(fp, "%s",demangled); > + free(res); > + } > + } else > + fprintf(fp, "%s", buf); > > if (msg_flags & SHOW_LOG_DICT) { > text = info + OFFSET(printk_info_dev_info) + > -- > 2.50.1 >