Report unhandled user faults the way other architectures do, and hook up the debug.exception-trace sysctl that controls the reporting.
The message gives the faulting address, the PC and the user stack pointer, and is rate limited. Assisted-by: Claude:claude-opus-5 Signed-off-by: Matt Turner <[email protected]> Tested-by: Magnus Lindholm <[email protected]> Reviewed-by: Magnus Lindholm <[email protected]> --- arch/alpha/Kconfig | 1 + arch/alpha/mm/fault.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index f2a5b8c8688a..b9ff67370877 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -61,6 +61,7 @@ config ALPHA select MMU_GATHER_NO_RANGE select MMU_GATHER_RCU_TABLE_FREE select SPARSEMEM_EXTREME if SPARSEMEM + select SYSCTL_EXCEPTION_TRACE select ZONE_DMA select TRACE_IRQFLAGS_SUPPORT select ARCH_WANT_FRAME_POINTERS diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index a9816bbc9f34..dfe427d93072 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -27,8 +27,32 @@ #include <linux/uaccess.h> #include <linux/perf_event.h> +#include <asm/pal.h> + extern void die_if_kernel(char *,struct pt_regs *,long, unsigned long *); +int show_unhandled_signals = 1; + +static void +show_signal_msg(struct pt_regs *regs, unsigned long address, int signo, + const char *desc) +{ + const char *level; + + if (!show_unhandled_signals || !unhandled_signal(current, signo)) + return; + if (!printk_ratelimit()) + return; + + /* Losing init is fatal, so shout about it. */ + level = task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG; + + printk("%s%s[%d]: %s at %016lx pc %016lx sp %016lx\n", + level, current->comm, task_pid_nr(current), desc, + address, regs->pc, rdusp()); + print_vma_addr(KERN_CONT " in ", regs->pc); + printk(KERN_CONT "\n"); +} /* * Force a new ASN for a task. @@ -217,12 +241,17 @@ do_page_fault(unsigned long address, unsigned long mmcsr, mmap_read_unlock(mm); /* Send a sigbus, regardless of whether we were in kernel or user mode. */ + if (user_mode(regs)) + show_signal_msg(regs, address, SIGBUS, "bus error"); force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address); if (!user_mode(regs)) goto no_context; return; do_sigsegv: + show_signal_msg(regs, address, SIGSEGV, + si_code == SEGV_MAPERR ? "unmapped access" + : "access violation"); force_sig_fault(SIGSEGV, si_code, (void __user *) address); return; -- 2.54.0
