• Vasily Gorbik's avatar
    kallsyms: exclude kasan local symbols on s390 · 33177f01
    Vasily Gorbik authored
    gcc asan instrumentation emits the following sequence to store frame pc
    when the kernel is built with CONFIG_RELOCATABLE:
    debug/vsprintf.s:
            .section        .data.rel.ro.local,"aw"
            .align  8
    .LC3:
            .quad   .LASANPC4826@GOTOFF
    .text
            .align  8
            .type   number, @function
    number:
    .LASANPC4826:
    
    and in case reloc is issued for LASANPC label it also gets into .symtab
    with the same address as actual function symbol:
    $ nm -n vmlinux | grep 0000000001397150
    0000000001397150 t .LASANPC4826
    0000000001397150 t number
    
    In the end kernel backtraces are almost unreadable:
    [  143.748476] Call Trace:
    [  143.748484] ([<000000002da3e62c>] .LASANPC2671+0x114/0x190)
    [  143.748492]  [<000000002eca1a58>] .LASANPC2612+0x110/0x160
    [  143.748502]  [<000000002de9d830>] print_address_description+0x80/0x3b0
    [  143.748511]  [<000000002de9dd64>] __kasan_report+0x15c/0x1c8
    [  143.748521]  [<000000002ecb56d4>] strrchr+0x34/0x60
    [  143.748534]  [<000003ff800a9a40>] kasan_strings+0xb0/0x148 [test_kasan]
    [  143.748547]  [<000003ff800a9bba>] kmalloc_tests_init+0xe2/0x528 [test_kasan]
    [  143.748555]  [<000000002da2117c>] .LASANPC4069+0x354/0x748
    [  143.748563]  [<000000002dbfbb16>] do_init_module+0x136/0x3b0
    [  143.748571]  [<000000002dbff3f4>] .LASANPC3191+0x2164/0x25d0
    [  143.748580]  [<000000002dbffc4c>] .LASANPC3196+0x184/0x1b8
    [  143.748587]  [<000000002ecdf2ec>] system_call+0xd8/0x2d8
    
    Since LASANPC labels are not even unique and get into .symtab only due
    to relocs filter them out in kallsyms.
    Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
    Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    33177f01
kallsyms.c 18 KB