89 lines
3.3 KiB
Diff
89 lines
3.3 KiB
Diff
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From 28891d1127542dbb2d5ba16c575e14e741ed73ef Mon Sep 17 00:00:00 2001
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From: Tao Liu <ltao@redhat.com>
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Date: Thu, 4 Jan 2024 09:20:27 +0800
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Subject: [PATCH 6/6] symbols: skip the module if the given address is not
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within its address range
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Previously, to find a module symbol and its offset by an arbitrary address,
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all symbols within the module will be iterated by address ascending order
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until the last symbol with a smaller address been noticed.
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However if the address is not within the module address range, e.g.
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the address is higher than the module's last symbol's address, then
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the module can be surely skipped, because its symbol iteration is
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unnecessary. This can speed up the kernel module symbols finding and improve
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the overall performance.
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Without the patch:
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$ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux
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crash> bt 8993
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PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0"
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#0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8
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#1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9
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#2 [ffff927569cd7768] __mutex_lock_slowpath at ffffffffb3db6ca7
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#3 [ffff927569cd77c0] mutex_lock at ffffffffb3db602f
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#4 [ffff927569cd77d8] ucache_retrieve at ffffffffc0cf4409 [secfs2]
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...snip the stacktrace of the same module...
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#11 [ffff927569cd7ba0] cskal_path_vfs_getattr_nosec at ffffffffc05cae76 [falcon_kal]
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...snip...
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#13 [ffff927569cd7c40] _ZdlPv at ffffffffc086e751 [falcon_lsm_serviceable]
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...snip...
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#20 [ffff927569cd7ef8] unload_network_ops_symbols at ffffffffc06f11c0 [falcon_lsm_pinned_14713]
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#21 [ffff927569cd7f50] system_call_fastpath at ffffffffb3dc539a
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RIP: 00007f2b28ed4023 RSP: 00007f2a45fe7f80 RFLAGS: 00000206
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RAX: 0000000000000012 RBX: 00007f2a68302e00 RCX: 00007f2a682546d8
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RDX: 0000000000000826 RSI: 00007eb57ea6a000 RDI: 00000000000000e3
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RBP: 00007eb57ea6a000 R8: 0000000000000826 R9: 00000002670bdfd2
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R10: 00000002670bdfd2 R11: 0000000000000293 R12: 00000002670bdfd2
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R13: 00007f29d501a480 R14: 0000000000000826 R15: 00000002670bdfd2
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ORIG_RAX: 0000000000000012 CS: 0033 SS: 002b
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crash>
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real 7m14.826s
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user 7m12.502s
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sys 0m1.091s
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With the patch:
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$ time echo "bt 8993" | ~/crash-dev/crash vmcore vmlinux
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crash> bt 8993
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PID: 8993 TASK: ffff927569cc2100 CPU: 2 COMMAND: "WriterPool0"
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#0 [ffff927569cd76f0] __schedule at ffffffffb3db78d8
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#1 [ffff927569cd7758] schedule_preempt_disabled at ffffffffb3db8bf9
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...snip the same output...
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crash>
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real 0m8.827s
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user 0m7.896s
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sys 0m0.938s
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Signed-off-by: Tao Liu <ltao@redhat.com>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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symbols.c | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/symbols.c b/symbols.c
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index 5d919910164e..88a3fd156cb5 100644
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--- a/symbols.c
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+++ b/symbols.c
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@@ -5561,7 +5561,7 @@ value_search_module_6_4(ulong value, ulong *offset)
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sp = lm->symtable[t];
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sp_end = lm->symend[t];
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- if (value < sp->value)
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+ if (value < sp->value || value > sp_end->value)
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continue;
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splast = NULL;
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@@ -5646,6 +5646,9 @@ retry:
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if (sp->value > value) /* invalid -- between modules */
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break;
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+ if (sp_end->value < value) /* not within the module */
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+ continue;
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+
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/*
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* splast will contain the last module symbol encountered.
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* Note: "__insmod_"-type symbols will be set in splast only
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--
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2.41.0
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