linux/scripts/kallsyms.c, branch v5.6

scripts/kallsyms: fix wrong kallsyms_relative_base

2020-03-19T14:40:20Z

There is the code in the read_symbol function in 'scripts/kallsyms.c': if (is_ignored_symbol(name, type)) return NULL; /* Ignore most absolute/undefined (?) symbols. */ if (strcmp(name, "_text") == 0) _text = addr; But the is_ignored_symbol function returns true for name="_text" and type='A'. So the next condition is not executed and the _text variable is always zero. It makes the wrong kallsyms_relative_base symbol as a result of the code (CONFIG_KALLSYMS_BASE_RELATIVE is defined): if (base_relative) { output_label("kallsyms_relative_base"); output_address(relative_base); printf("\n"); } Because the output_address function uses the _text variable. So the kallsyms_lookup function and all related functions in the kernel do not work properly. For example, the stack trace in oops: Call Trace: [aa095e58] [809feab8] kobj_ns_ops_tbl+0x7ff09ac8/0x7ff1c1c4 (unreliable) [aa095e98] [80002b64] kobj_ns_ops_tbl+0x7f50db74/0x80000010 [aa095ef8] [809c3d24] kobj_ns_ops_tbl+0x7feced34/0x7ff1c1c4 [aa095f28] [80002ed0] kobj_ns_ops_tbl+0x7f50dee0/0x80000010 [aa095f38] [8000f238] kobj_ns_ops_tbl+0x7f51a248/0x80000010 The right stack trace: Call Trace: [aa095e58] [809feab8] module_vdu_video_init+0x2fc/0x3bc (unreliable) [aa095e98] [80002b64] do_one_initcall+0x40/0x1f0 [aa095ef8] [809c3d24] kernel_init_freeable+0x164/0x1d8 [aa095f28] [80002ed0] kernel_init+0x14/0x124 [aa095f38] [8000f238] ret_from_kernel_thread+0x14/0x1c [masahiroy@kernel.org: This issue happens on binutils <= 2.22 The following commit fixed it: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d2667025dd30611514810c28bee9709e4623012a The symbol type of _text is 'T' on binutils >= 2.23 The minimal supported binutils version for the kernel build is 2.21 ] Signed-off-by: Mikhail Petrov Signed-off-by: Masahiro Yamada

scripts/kallsyms: fix memory corruption caused by write over-run

2020-02-10T20:18:09Z

memcpy() writes one more byte than allocated. Fixes: 8d60526999aa ("scripts/kallsyms: change table to store (strcut sym_entry *)") Reported-by: youling257 Reported-by: Pavel Machek Signed-off-by: Masahiro Yamada Tested-by: Pavel Machek

scripts/kallsyms: change table to store (strcut sym_entry *)

2020-02-03T16:54:30Z

The symbol table is extended every 10000 addition by using realloc(), where data copy might occur to the new buffer. To decrease the amount of possible data copy, let's change the table to store the pointer. The symbol type + symbol name part is appended at the end of (struct sym_entry), and allocated together with the struct body. Signed-off-by: Masahiro Yamada

scripts/kallsyms: rename local variables in read_symbol()

2020-02-03T16:54:15Z

I will use 'sym' for the point to struce sym_entry in the next commit. Rename 'sym', 'stype' to 'name', 'type', which are more intuitive. Signed-off-by: Masahiro Yamada

scripts/kallsyms: fix offset overflow of kallsyms_relative_base

2019-12-14T06:53:04Z

Since commit 5e5c4fa78745 ("scripts/kallsyms: shrink table before sorting it"), kallsyms_relative_base can be larger than _text, which causes overflow when building the 32-bit kernel. https://lkml.org/lkml/2019/12/7/156 This is because _text is, unless --all-symbols is specified, now trimmed from the symbol table before record_relative_base() is called. Handle the offset signedness also for kallsyms_relative_base. Introduce a new helper, output_address(), to reduce the code duplication. Fixes: 5e5c4fa78745 ("scripts/kallsyms: shrink table before sorting it") Reported-by: Olof Johansson Signed-off-by: Masahiro Yamada

scripts/kallsyms: remove redundant initializers

2019-11-25T12:07:05Z

These are set to zero without the explicit initializers. Signed-off-by: Masahiro Yamada

scripts/kallsyms: put check_symbol_range() calls close together

2019-11-25T12:06:49Z

Put the relevant code close together. Signed-off-by: Masahiro Yamada

scripts/kallsyms: make check_symbol_range() void function

2019-11-25T12:06:37Z

There is no more reason to check the return value of check_symbol_range(). Signed-off-by: Masahiro Yamada

scripts/kallsyms: move ignored symbol types to is_ignored_symbol()

2019-11-25T12:06:14Z

Collect the ignored patterns to is_ignored_symbol(). Signed-off-by: Masahiro Yamada

scripts/kallsyms: move more patterns to the ignored_prefixes array

2019-11-25T12:06:01Z

Refactoring for shortening the code. Signed-off-by: Masahiro Yamada