__get_kernel_nofault() does copy data in supervisor mode when forcing a task backtrace dump through the sysrq trigger. Our 030 bus error handler is ill equipped to deal with this: Whenever ssw indicates a kernel mode access on a data fault, we don't even attempt to handle the fault and instead send a bus error signal (or panic). As a result, the check for exception handling at the fault PC (buried in send_sig_fault() which gets called from do_page_fault() eventually) is never used. Both 040 and 060 access error handlers do not care whether a fault happened on supervisor mode access, and will call do_page_fault() even on those. Add a check in bus_error030 to call do_page_fault() in case we do have an entry for the fault PC in our exception table. Tested on 030 Atari Falcon. Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx># Please enter the commit message for your changes. Lines starting CC: Eero Tamminen <oak@xxxxxxxxxxxxxx> CC: Finn Thain <ftain@xxxxxxxxxxxxxx> CC: Andreas Schwab <schwab@xxxxxxxxxxxxxx> CC: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/daca2f68-19fa-a2b6-97c6-16b5b7e26afe@xxxxxxxxxxxxxx --- arch/m68k/kernel/traps.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c index 5c8cba0efc63..67576fb0c466 100644 --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -30,6 +30,7 @@ #include <linux/init.h> #include <linux/ptrace.h> #include <linux/kallsyms.h> +#include <linux/extable.h> #include <asm/setup.h> #include <asm/fpu.h> @@ -545,7 +546,7 @@ static inline void bus_error030 (struct frame *fp) errorcode |= 2; if (mmusr & (MMU_I | MMU_WP)) { - if (ssw & 4) { + if (ssw & 4 && !search_exception_tables(fp->ptregs.pc)) { pr_err("Data %s fault at %#010lx in %s (pc=%#lx)\n", ssw & RW ? "read" : "write", fp->un.fmtb.daddr, -- 2.17.1
