On Tue, Sep 16, 2025 at 4:19 PM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab@nec.com> wrote:

On 2025/09/16 16:37, lijiang wrote:
> On Tue, Sep 16, 2025 at 2:26 PM lijiang <lijiang@redhat.com <mailto:lijiang@redhat.com>> wrote:
>
> On Tue, Sep 16, 2025 at 12:51 PM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab@nec.com <mailto:k-hagio-ab@nec.com>> wrote:
>
> Hi Lianbo, Tao,
>
> Just a report, with this patch (99bb57ac98af), I observed that
> the log command printed a couple of empty lines (only timestamps).
> Could you reproduce this at your end?
>
>
> Thank you for reporting this, Kazu.
> I will check it, and did not see it before this.
>
> Could you please try this one? Kazu.

Sure, the patch below fixed the issue at my end.

Good news.

Thank you so much, Kazu.

Lianbo

Thanks,
Kazu

>
> diff --git a/printk.c b/printk.c
> index ae28c4f..51b618e 100644
> --- a/printk.c
> +++ b/printk.c
> @@ -221,7 +221,7 @@ dump_record(struct prb_map *m, unsigned long id, int msg_flags)
> char *p1 = strstr(buf, "_R");
> if (!p1)
> p1 = strstr(buf, "_ZN");
> - char *p2 = strchrnul(buf, '+');
> + char *p2 = strrchr(buf, '+');
> if (p1 && p2) {
> char mangled[BUFSIZE] = {0};
> char demangled[BUFSIZE] = {0};
>
> I did not reproduce it, but I guess that this should be related to the strchrnul(), let's replace it with the strrchr().
>
> Thanks.
> Lianbo
>
>
> Thanks.
> Lianbo
>
>
> $ diff -u log.pre log.cur
> --- log.pre 2025-09-16 13:14:31.022206514 +0900
> +++ log.cur 2025-09-16 13:14:56.220390987 +0900
> @@ -210,7 +210,7 @@
> [ 0.169375] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275000 ns
> [ 0.169375] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
> [ 0.169375] pinctrl core: initialized pinctrl subsystem
> -[ 0.172925] NET: Registered PF_NETLINK/PF_ROUTE protocol family
> +[ 0.172925]
> [ 0.172983] DMA: preallocated 512 KiB GFP_KERNEL pool for atomic allocations
> [ 0.172986] DMA: preallocated 512 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations
> [ 0.172988] DMA: preallocated 512 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
> @@ -807,7 +807,7 @@
> [771438.513231] entry_SYSCALL_64_after_hwframe+0x72/0xdc
> [771438.513423] RIP: 0033:0x7fbd9f8fda57
> [771438.513576] Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
> -[771438.514251] RSP: 002b:00007ffee0de2b98 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> +[771438.514251]
> [771438.514534] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fbd9f8fda57
> [771438.514800] RDX: 0000000000000002 RSI: 00005647ccc0a330 RDI: 0000000000000001
> [771438.515066] RBP: 00005647ccc0a330 R08: 0000000000000003 R09: 0000000000000000
>
> log.cur: 99bb57ac98afd89fcf23f0c8bc637821dcbd278f
> log.pre: a5942e3acfd9330d101cc65ef2e19e627233ddf6
> vmcore: panic by sysrq-trigger on 5.14.0-427.13.1.el9_4.x86_64
> (found also on 6.17-rc6)
>
> Thanks,
> Kazu
>
> On 2025/09/15 10:19, Tao Liu wrote:
> > applied: https://github.com/crash-utility/crash/commit/99bb57ac98afd89fcf23f0c8bc637821dcbd278f <https://github.com/crash-utility/crash/commit/99bb57ac98afd89fcf23f0c8bc637821dcbd278f>
> >
> > On Wed, Sep 10, 2025 at 2:33 PM Tao Liu <ltao@redhat.com <mailto:ltao@redhat.com>> wrote:
> >>
> >> Hi lianbo,
> >>
> >> Thanks for the v2, LGTM, ack.
> >>
> >>
> >> On Mon, Sep 8, 2025 at 8:42 PM Lianbo Jiang <lijiang@redhat.com <mailto:lijiang@redhat.com>> 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@redhat.com <mailto:lijiang@redhat.com>>
> >>> ---
> >>> 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
> >>>
> > --
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