[Crash-utility] Re: [PATCH] symbols: skip the module if the given address is not within its address range

Hi, Tao Thank you for the fix. On 1/4/24 23:27, devel-request(a)lists.crash-utility.osci.io wrote: > Date: Thu, 4 Jan 2024 09:20:27 +0800 > From: Tao Liu&lt;ltao(a)redhat.com&gt; > Subject: [Crash-utility] [PATCH] symbols: skip the module if the given > address is not within its address range > To:devel@lists.crash-utility.osci.io > Cc: Tao Liu&lt;ltao(a)redhat.com&gt; > Message-ID:<20240104012027.3893-1-ltao@redhat.com> > Content-Type: text/plain; charset="US-ASCII"; x-default=true > > Previously, to find a module symbol and its offset by an arbitrary address, > all symbols within the module will be iterated by address ascending order > until the last symbol with a smaller address been noticed. > > However if the address is not within the module address range, e.g. > the address is higher than the module's last symbol's address, then > the module can be surely skipped, because its symbol iteration is > unnecessary. This can speed up the kernel module symbols finding and improve > the overall performance. > > Without the patch: > $ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux > crash> bt 8993 > PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0" > #0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8 > #1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9 > #2 [ffff927569cd7768] __mutex_lock_slowpath at ffffffffb3db6ca7 > #3 [ffff927569cd77c0] mutex_lock at ffffffffb3db602f > #4 [ffff927569cd77d8] ucache_retrieve at ffffffffc0cf4409 [secfs2] > ...snip the stacktrace of the same module... > #11 [ffff927569cd7ba0] cskal_path_vfs_getattr_nosec at ffffffffc05cae76 [falcon_kal] > ...snip... > #13 [ffff927569cd7c40] _ZdlPv at ffffffffc086e751 [falcon_lsm_serviceable] > ...snip... > #20 [ffff927569cd7ef8] unload_network_ops_symbols at ffffffffc06f11c0 [falcon_lsm_pinned_14713] > #21 [ffff927569cd7f50] system_call_fastpath at ffffffffb3dc539a > RIP: 00007f2b28ed4023 RSP: 00007f2a45fe7f80 RFLAGS: 00000206 > RAX: 0000000000000012 RBX: 00007f2a68302e00 RCX: 00007f2a682546d8 > RDX: 0000000000000826 RSI: 00007eb57ea6a000 RDI: 00000000000000e3 > RBP: 00007eb57ea6a000 R8: 0000000000000826 R9: 00000002670bdfd2 > R10: 00000002670bdfd2 R11: 0000000000000293 R12: 00000002670bdfd2 > R13: 00007f29d501a480 R14: 0000000000000826 R15: 00000002670bdfd2 > ORIG_RAX: 0000000000000012 CS: 0033 SS: 002b > crash> > real 7m14.826s > user 7m12.502s > sys 0m1.091s > > With the patch: > $ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux > crash> bt 8993 > PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0" > #0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8 > #1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9 > ...snip the same output... > crash> > real 0m8.827s > user 0m7.896s > sys 0m0.938s > > Signed-off-by: Tao Liu&lt;ltao(a)redhat.com&gt; > --- > symbols.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) This looks good to me, so: Ack.

Thanks Lianbo > diff --git a/symbols.c b/symbols.c > index 5d91991..88a3fd1 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -5561,7 +5561,7 @@ value_search_module_6_4(ulong value, ulong *offset) > sp = lm->symtable[t]; > sp_end = lm->symend[t]; > > - if (value < sp->value) > + if (value < sp->value || value > sp_end->value) > continue; > > splast = NULL; > @@ -5646,6 +5646,9 @@ retry: > if (sp->value > value) /* invalid -- between modules */ > break; > > + if (sp_end->value < value) /* not within the module */ > + continue; > + > /* > * splast will contain the last module symbol encountered. > * Note: "__insmod_"-type symbols will be set in splast only > -- 2.40.1 -- Crash-utility mailing list -- devel(a)lists.crash-utility.osci.io To unsubscribe send an email to devel-leave(a)lists.crash-utility.osci.io https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki