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    Subject[PATCH v2 1/9] powerpc: Remove __kernel_text_address() in show_instructions()
    Date
    That test was introducted in 2006 by
    commit 00ae36de49cc ("[POWERPC] Better check in show_instructions").
    At that time, there was no BPF progs.

    As seen in message of commit 89d21e259a94 ("powerpc/bpf/32: Fix Oops
    on tail call tests"), when a page fault occurs in test_bpf.ko for
    instance, the code is dumped as XXXXXXXXs. Allthough
    __kernel_text_address() checks is_bpf_text_address(), it seems it is
    not enough.

    Today, show_instructions() uses get_kernel_nofault() to read the code,
    so there is no real need for additional verifications.

    ARM64 and x86 don't do any additional check before dumping
    instructions. Do the same and remove __kernel_text_address()
    in show_instructions().

    Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
    ---
    arch/powerpc/kernel/process.c | 3 +--
    1 file changed, 1 insertion(+), 2 deletions(-)

    diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
    index c22cc234672f..effe9697905d 100644
    --- a/arch/powerpc/kernel/process.c
    +++ b/arch/powerpc/kernel/process.c
    @@ -1405,8 +1405,7 @@ static void show_instructions(struct pt_regs *regs)
    for (i = 0; i < NR_INSN_TO_PRINT; i++) {
    int instr;

    - if (!__kernel_text_address(pc) ||
    - get_kernel_nofault(instr, (const void *)pc)) {
    + if (get_kernel_nofault(instr, (const void *)pc)) {
    pr_cont("XXXXXXXX ");
    } else {
    if (nip == pc)
    --
    2.39.1
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