On Mon, 23 Sep 2019, Vincent Chen wrote: > For the kernel space, all ebreak instructions are determined at compile > time because the kernel space debugging module is currently unsupported. > Hence, it should be treated as a bug if an ebreak instruction which does > not belong to BUG_TRAP_TYPE_WARN or BUG_TRAP_TYPE_BUG is executed in > kernel space. For the userspace, debugging module or user problem may > intentionally insert an ebreak instruction to trigger a SIGTRAP signal. > To approach the above two situations, the do_trap_break() will direct > the BUG_TRAP_TYPE_NONE ebreak exception issued in kernel space to die() > and will send a SIGTRAP to the trapped process only when the ebreak is > in userspace. > > Signed-off-by: Vincent Chen <[email protected]>
Thanks, queued the following for v5.4-rc. - Paul From: Vincent Chen <[email protected]> Date: Mon, 23 Sep 2019 08:45:16 +0800 Subject: [PATCH] riscv: Correct the handling of unexpected ebreak in do_trap_break() For the kernel space, all ebreak instructions are determined at compile time because the kernel space debugging module is currently unsupported. Hence, it should be treated as a bug if an ebreak instruction which does not belong to BUG_TRAP_TYPE_WARN or BUG_TRAP_TYPE_BUG is executed in kernel space. For the userspace, debugging module or user problem may intentionally insert an ebreak instruction to trigger a SIGTRAP signal. To approach the above two situations, the do_trap_break() will direct the BUG_TRAP_TYPE_NONE ebreak exception issued in kernel space to die() and will send a SIGTRAP to the trapped process only when the ebreak is in userspace. Signed-off-by: Vincent Chen <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> [[email protected]: fixed checkpatch issue] Signed-off-by: Paul Walmsley <[email protected]> --- arch/riscv/kernel/traps.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 82f42a55451e..93742df9067f 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -130,8 +130,6 @@ asmlinkage void do_trap_break(struct pt_regs *regs) type = report_bug(regs->sepc, regs); switch (type) { #ifdef CONFIG_GENERIC_BUG - case BUG_TRAP_TYPE_NONE: - break; case BUG_TRAP_TYPE_WARN: regs->sepc += get_break_insn_length(regs->sepc); return; @@ -140,8 +138,10 @@ asmlinkage void do_trap_break(struct pt_regs *regs) default: die(regs, "Kernel BUG"); } + } else { + force_sig_fault(SIGTRAP, TRAP_BRKPT, + (void __user *)(regs->sepc)); } - force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc)); } #ifdef CONFIG_GENERIC_BUG -- 2.23.0
