diff options
| author | Will Deacon <will.deacon@arm.com> | 2014-07-31 11:36:08 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2014-07-31 11:36:08 +0100 |
| commit | c878e0cff5c5e56b216951cbe75f7a3dd500a736 (patch) | |
| tree | 234fca64e4707b18b7c1bfe354348e9a096badbf | |
| parent | 3666f88010d71e752ad677ec64edf148366afb7a (diff) | |
| download | linux-c878e0cff5c5e56b216951cbe75f7a3dd500a736.tar.bz2 | |
arm64: don't call break hooks for BRK exceptions from EL0
Our break hooks are used to handle brk exceptions from kgdb (and potentially
kprobes if that code ever resurfaces), so don't bother calling them if
the BRK exception comes from userspace.
This prevents userspace from trapping to a kdb shell on systems where
kgdb is enabled and active.
Cc: <stable@vger.kernel.org>
Reported-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/kernel/debug-monitors.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index a7fb874b595e..fe5b94078d82 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -315,20 +315,20 @@ static int brk_handler(unsigned long addr, unsigned int esr, { siginfo_t info; - if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED) - return 0; + if (user_mode(regs)) { + info = (siginfo_t) { + .si_signo = SIGTRAP, + .si_errno = 0, + .si_code = TRAP_BRKPT, + .si_addr = (void __user *)instruction_pointer(regs), + }; - if (!user_mode(regs)) + force_sig_info(SIGTRAP, &info, current); + } else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) { + pr_warning("Unexpected kernel BRK exception at EL1\n"); return -EFAULT; + } - info = (siginfo_t) { - .si_signo = SIGTRAP, - .si_errno = 0, - .si_code = TRAP_BRKPT, - .si_addr = (void __user *)instruction_pointer(regs), - }; - - force_sig_info(SIGTRAP, &info, current); return 0; } |