134 lines
4.0 KiB
Diff
134 lines
4.0 KiB
Diff
From 5948cb9b3e622e3c87216c7c6479f509c8aeb7c1 Mon Sep 17 00:00:00 2001
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From: Tao Liu <ltao@redhat.com>
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Date: Wed, 16 Nov 2022 17:36:03 +0800
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Subject: [PATCH 18/28] Let gdb get kernel module symbols info from crash
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Gdb will try to resolve an address to its corresponding symbol name such as
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when printing a structure. It works fine for kernel symbols, because gdb can
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find them through vmlinux. However as for kernel modules symbols, crash
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resolves them by dig into "struct module", which gdb don't know. As a result,
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gdb fails to translate a kernel module address to its symbol name without
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"mod -s|-S" options. For example we can reproduce the issue as follows.
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crash> timer
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....
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4331308176 336 ffff94ea24240860 ffffffffc03762c0 <estimation_timer>
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....
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crash> sym 0xffffffffc03762c0
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ffffffffc03762c0 (t) estimation_timer [ip_vs]
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Before patch:
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crash> timer_list ffff94ea24240860
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struct timer_list {
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....
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function = 0xffffffffc03762c0,
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....
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}
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After patch:
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crash> timer_list ffff94ea24240860
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struct timer_list {
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....
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function = 0xffffffffc03762c0 <estimation_timer>,
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....
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}
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In this patch, we add an interface for gdb, when gdb trying to build kernel
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module's address symbolic, the info can be get from crash.
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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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defs.h | 2 ++
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gdb-7.6.patch | 33 +++++++++++++++++++++++++++++++++
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gdb_interface.c | 12 ++++++++++++
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3 files changed, 47 insertions(+)
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diff --git a/defs.h b/defs.h
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index f8fbfdfd1152..b7d76330141a 100644
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--- a/defs.h
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+++ b/defs.h
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@@ -4877,6 +4877,7 @@ int patch_kernel_symbol(struct gnu_request *);
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struct syment *symbol_search(char *);
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int gdb_line_number_callback(ulong, ulong, ulong);
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int gdb_print_callback(ulong);
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+char *gdb_lookup_module_symbol(ulong, ulong *);
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#endif
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#ifndef GDB_COMMON
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@@ -7291,6 +7292,7 @@ int gdb_pass_through(char *, FILE *, ulong);
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int gdb_readmem_callback(ulong, void *, int, int);
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int gdb_line_number_callback(ulong, ulong, ulong);
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int gdb_print_callback(ulong);
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+char *gdb_lookup_module_symbol(ulong, ulong *);
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void gdb_error_hook(void);
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void restore_gdb_sanity(void);
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int is_gdb_command(int, ulong);
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diff --git a/gdb-7.6.patch b/gdb-7.6.patch
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index c63ad7d81cb0..f1c3aa734241 100644
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--- a/gdb-7.6.patch
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+++ b/gdb-7.6.patch
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@@ -2568,3 +2568,36 @@ diff -up gdb-7.6/opcodes/configure.orig gdb-7.6/opcodes/configure
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$(CC_LD) $(INTERNAL_LDFLAGS) $(WIN32LDAPP) \
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-o $(shell /bin/cat mergeobj) $(LIBGDB_OBS) \
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$(TDEPLIBS) $(TUI_LIBRARY) $(CLIBS) $(LOADLIBES) $(shell /bin/cat mergelibs)
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+--- gdb-7.6/gdb/printcmd.c.orig
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++++ gdb-7.6/gdb/printcmd.c
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+@@ -622,6 +622,10 @@ print_address_symbolic (struct gdbarch *gdbarch, CORE_ADDR addr,
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+ return 1;
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+ }
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+
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++#ifdef CRASH_MERGE
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++extern char *gdb_lookup_module_symbol(unsigned long, unsigned long *);
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++#endif
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++
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+ /* Given an address ADDR return all the elements needed to print the
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+ address in a symbolic form. NAME can be mangled or not depending
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+ on DO_DEMANGLE (and also on the asm_demangle global variable,
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+@@ -710,7 +714,19 @@ build_address_symbolic (struct gdbarch *gdbarch,
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+ }
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+ }
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+ if (symbol == NULL && msymbol == NULL)
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++#ifdef CRASH_MERGE
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++ {
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++ char *name_ptr = gdb_lookup_module_symbol(addr, (unsigned long *)offset);
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++ if (name_ptr) {
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++ *name = xstrdup (name_ptr);
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++ return 0;
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++ } else {
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++ return 1;
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++ }
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++ }
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++#else
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+ return 1;
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++#endif
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+
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+ /* If the nearest symbol is too far away, don't print anything symbolic. */
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+
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diff --git a/gdb_interface.c b/gdb_interface.c
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index 1f10006a2d63..f9d0018998df 100644
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--- a/gdb_interface.c
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+++ b/gdb_interface.c
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@@ -945,6 +945,18 @@ gdb_print_callback(ulong addr)
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return IS_KVADDR(addr);
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}
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+char *
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+gdb_lookup_module_symbol(ulong addr, ulong *offset)
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+{
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+ struct syment *sp;
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+
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+ if ((sp = value_search(addr, offset))) {
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+ return sp->name;
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+ } else {
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+ return NULL;
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+ }
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+}
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+
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/*
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* Used by gdb_interface() to catch gdb-related errors, if desired.
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*/
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--
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2.37.1
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