From: Mark Rutland Date: Tue, 7 Dec 2021 18:32:25 +0000 (+0000) Subject: arm64: mm: use die_kernel_fault() in do_mem_abort() X-Git-Tag: v6.6.17~8339^2~3^6~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6f6cfa5867995c03959ce8c715e54b51cd5a1528;p=platform%2Fkernel%2Flinux-rpi.git arm64: mm: use die_kernel_fault() in do_mem_abort() If we take an unhandled fault from EL1, either: a) The xFSC handler calls die_kernel_fault() directly. In this case, die_kernel_fault() calls: pr_alert(..., msg, addr); mem_abort_decode(esr); show_pte(addr); die(); bust_spinlocks(0); do_exit(SIGKILL); b) The xFSC handler returns to do_mem_abort(), indicating failure. In this case, do_mem_abort() calls: pr_alert(..., addr); mem_abort_decode(esr); show_pte(addr); arm64_notify_die() { die(); } This inconstency is unfortunatem, and in theory in case (b) registered notifiers can prevent us from terminating the faulting thread by returning NOTIFY_STOP, whereupon we'll end up returning from the fault, replaying, and almost certainly get stuck in a livelock spewing errors into dmesg. We don't expect notifers to fix things up, since we dump state to dmesg before invoking them, so it would be more sensible to consistently terminate the thread in this case. This patch has do_mem_abort() call die_kernel_fault() for unhandled faults taken from EL1. Where we would previously have logged a messafe of the form: | Unhandled fault at ${ADDR} ... we will now log a message of the form: | Unable to handle kernel ${FAULT_NAME} at virtual address ${ADDR} ... and we will consistently terminate the thread from which the fault was taken. Signed-off-by: Mark Rutland Cc: Will Deacon Tested-by: Andrey Konovalov Acked-by: Will Deacon Link: https://lore.kernel.org/r/20211207183226.834557-2-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 9ae24e3..b7b9caa 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -813,11 +813,8 @@ void do_mem_abort(unsigned long far, unsigned int esr, struct pt_regs *regs) if (!inf->fn(far, esr, regs)) return; - if (!user_mode(regs)) { - pr_alert("Unhandled fault at 0x%016lx\n", addr); - mem_abort_decode(esr); - show_pte(addr); - } + if (!user_mode(regs)) + die_kernel_fault(inf->name, addr, esr, regs); /* * At this point we have an unrecognized fault type whose tag bits may