[Crash-utility] Re: [PATCH] Fix for log command printed a couple of empty lines

Hi Lianbo, Thanks for the fix, LGTM, ack. Thanks, Tao Liu On Tue, Sep 16, 2025 at 8:05 PM Lianbo Jiang <lijiang(a)redhat.com&gt; wrote: > > The log command printed a couple of empty lines (only timestamps), which > was caused by the commit 99bb57ac98af ("Enable resolving mangled Rust > symbol in lockless ring buffer"), E.g: > > $ 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 > > This is because the strchrnul() returns a pointer to the null byte > instead NULL if the char to be searched is not in the string. Given > that, let's replace the strchrnul() with the strrchr(). > > Fixes: 99bb57ac98af ("Enable resolving mangled Rust symbol in lockless ring buffer") > Reported-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; > --- > printk.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/printk.c b/printk.c > index ae28c4fa0b21..51b618e2a434 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}; > -- > 2.50.1 >