Messages in this thread | | | Date | Tue, 26 Jun 2018 22:05:29 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v3] arch/x86: get rid of KERN_CONT in show_fault_oops() |
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* Dmitry Vyukov <dvyukov@gmail.com> wrote:
> From: Dmitry Vyukov <dvyukov@google.com> > > KERN_CONT leads to split lines in kernel output > and complicates useful changes to printk like > printing context before each line. > > Only acceptable use of continuations is basically > boot-time testing. > > Get rid of it. > > Also tidy up code around as asked by reviewers. > > Signed-off-by: Dmitry Vyukov <dvyukov@google.com> > Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> > > --- > > Changes since v1: > - use pr_alert() instead of printk(KERN_ALERT) > > Changes since v2: > - drop unnecessary parenthesis > - remove once used nx_warning and smep_warning > --- > arch/x86/mm/fault.c | 21 +++++++-------------- > 1 file changed, 7 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 9a84a0d08727..a73575cacfd9 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -641,11 +641,6 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address) > return 0; > } > > -static const char nx_warning[] = KERN_CRIT > -"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n"; > -static const char smep_warning[] = KERN_CRIT > -"unable to execute userspace code (SMEP?) (uid: %d)\n"; > - > static void > show_fault_oops(struct pt_regs *regs, unsigned long error_code, > unsigned long address) > @@ -664,20 +659,18 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, > pte = lookup_address_in_pgd(pgd, address, &level); > > if (pte && pte_present(*pte) && !pte_exec(*pte)) > - printk(nx_warning, from_kuid(&init_user_ns, current_uid())); > + pr_crit("kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n", > + from_kuid(&init_user_ns, current_uid())); > if (pte && pte_present(*pte) && pte_exec(*pte) && > (pgd_flags(*pgd) & _PAGE_USER) && > (__read_cr4() & X86_CR4_SMEP)) > - printk(smep_warning, from_kuid(&init_user_ns, current_uid())); > + pr_crit("unable to execute userspace code (SMEP?) (uid: %d)\n", > + from_kuid(&init_user_ns, current_uid())); > } > > - printk(KERN_ALERT "BUG: unable to handle kernel "); > - if (address < PAGE_SIZE) > - printk(KERN_CONT "NULL pointer dereference"); > - else > - printk(KERN_CONT "paging request"); > - > - printk(KERN_CONT " at %px\n", (void *) address); > + pr_alert("BUG: unable to handle kernel %s at %px\n", > + address < PAGE_SIZE ? "NULL pointer dereference" : > + "paging request", (void *) address);
I already applied the last hunk in a bit different way - could you send the rest as a separate clean-up patch please?
Thanks,
Ingo
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