[Crash-utility] [PATCH 1/2] x86: check the __ia32_sys_* symbols for frame pointers

On 32-bit x86 kernels the syscall entry wrappers are named __ia32_sys_open, __ia32_sys_fork and __ia32_sys_read; the legacy sys_open, sys_fork and sys_read symbols do not exist there. Even so, x86_omit_frame_pointer() still looked up the legacy names, and symbol_value() aborted the session during initialization with: crash: cannot resolve "sys_open" Add the __ia32_sys_* variants and skip names that are not present in the kernel symbol table, matching x86_64_framepointer_init(). Keep the legacy names first so that older kernels, which only provide the sys_* wrappers, remain supported; the missing names are skipped on both old and new kernels. Also iterate over all six entries: the loop previously stopped after two, so the third legacy name was never checked. Tested with the 32-bit i686 7.3.0-rc2 kdump and matching vmlinux: the session initializes, "bt" resolves __ia32_sys_write, and no "cannot resolve" error is reported. Fixes: https://github.com/crash-utility/crash/issues/116 Signed-off-by: Dave Young <yangrr.2009(a)tsinghua.org.cn&gt; --- x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/x86.c b/x86.c index b36f44c54819..fe175aa5bcb0 100644 --- a/x86.c +++ b/x86.c @@ -4482,12 +4482,16 @@ x86_omit_frame_pointer(void) { ulonglong push_bp_mov_esp_bp; int i; - char *checkfuncs[] = {"sys_open", "sys_fork", "sys_read"}; + char *checkfuncs[] = {"sys_open", "sys_fork", "sys_read", + "__ia32_sys_open", "__ia32_sys_fork", + "__ia32_sys_read"}; if (pc->flags & KERNEL_DEBUG_QUERY) return FALSE; - for (i = 0; i < 2; i++) { + for (i = 0; i < 6; i++) { + if(!kernel_symbol_exists(checkfuncs[i])) + continue; if (!readmem(symbol_value(checkfuncs[i]), KVADDR, &push_bp_mov_esp_bp, sizeof(ulonglong), "x86_omit_frame_pointer", RETURN_ON_ERROR)) -- 2.51.1