78 lines
3.2 KiB
Diff
78 lines
3.2 KiB
Diff
From eedf12d4758409c3c405f56edf3177a3955e1f67 Mon Sep 17 00:00:00 2001
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From: Lianbo Jiang <lijiang@redhat.com>
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Date: Wed, 6 Mar 2024 14:31:27 +0800
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Subject: [PATCH] gdb: fix "p" command to print module variables correctly
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Some objects format may potentially support copy relocations, but
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currently the maybe_copied is always initialized to 0 in the symbol().
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And the type is 'mst_file_bss', not always the 'mst_bss' or 'mst_data'
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in the lookup_minimal_symbol_linkage(). For example:
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(gdb) p *msymbol
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$42 = {<general_symbol_info> = {m_name = 0x349812f "test_no_static", value = {ivalue = 8, block = 0x8,
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bytes = 0x8 <error: Cannot access memory at address 0x8>, address = 8, common_block = 0x8, chain = 0x8}, language_specific = {
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obstack = 0x0, demangled_name = 0x0}, m_language = language_auto, ada_mangled = 0, section = 20}, size = 4,
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filename = 0x6db3440 "test_sanity.c", type = mst_file_bss, created_by_gdb = 0, target_flag_1 = 0, target_flag_2 = 0, has_size = 1,
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maybe_copied = 0, name_set = 1, hash_next = 0x0, demangled_hash_next = 0x0}
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This causes a problem that the 'p' command cannot work well as expected,
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and emits an error or a bogus value:
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crash> mod -s test_sanity /home/test_sanity.ko
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MODULE NAME BASE SIZE OBJECT FILE
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ffffffffc1084040 test_sanity ffffffffc1082000 16384 /home/test_sanity.ko
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crash> p test_no_static
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p: gdb request failed: p test_no_static
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crash>
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The issue occurs with Linux 6.2 and later or kernels that have kernel
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commit 80e4c1cd42ff ("x86/retbleed: Add X86_FEATURE_CALL_DEPTH") and
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configured with CONFIG_CALL_DEPTH_TRACKING=y, including RHEL9.3 and
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later kernels.
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With the patch:
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crash> mod -s test_sanity /home/test_sanity.ko
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MODULE NAME BASE SIZE OBJECT FILE
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ffffffffc1084040 test_sanity ffffffffc1082000 16384 /home/test_sanity.ko
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crash> p test_no_static
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test_no_static = $1 = 5
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crash>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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gdb-10.2.patch | 24 ++++++++++++++++++++++++
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1 file changed, 24 insertions(+)
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diff --git a/gdb-10.2.patch b/gdb-10.2.patch
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index 7416efed..3694b131 100644
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--- a/gdb-10.2.patch
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+++ b/gdb-10.2.patch
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@@ -3237,3 +3237,27 @@ exit 0
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for (compunit_symtab *cust : objfile->compunits ())
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{
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+--- gdb-10.2/gdb/minsyms.c.orig
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++++ gdb-10.2/gdb/minsyms.c
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+@@ -535,7 +535,9 @@ lookup_minimal_symbol_linkage (const char *name, struct objfile *objf)
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+ {
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+ if (strcmp (msymbol->linkage_name (), name) == 0
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+ && (MSYMBOL_TYPE (msymbol) == mst_data
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+- || MSYMBOL_TYPE (msymbol) == mst_bss))
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++ || MSYMBOL_TYPE (msymbol) == mst_bss
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++ || MSYMBOL_TYPE (msymbol) == mst_file_bss
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++ || MSYMBOL_TYPE (msymbol) == mst_file_data))
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+ return {msymbol, objfile};
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+ }
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+ }
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+--- gdb-10.2/gdb/symtab.h.orig
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++++ gdb-10.2/gdb/symtab.h
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+@@ -1110,7 +1110,7 @@ struct symbol : public general_symbol_info, public allocate_on_obstack
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+ is_objfile_owned (1),
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+ is_argument (0),
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+ is_inlined (0),
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+- maybe_copied (0),
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++ maybe_copied (1), /* The objfile potentially supports copy relocations. */
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+ subclass (SYMBOL_NONE)
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+ {
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+ /* We can't use an initializer list for members of a base class, and
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