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| author | David Miller <davem@redhat.com> | 2018-10-25 20:36:46 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-10-26 15:04:41 -0700 |
| commit | 5b4fc3882a649c9411dd0dcad2ddb78e911d340e (patch) | |
| tree | 1e4d71d14473c440a48f1fbfdcd465cf478fc2f4 /arch/sparc/kernel/process_64.c | |
| parent | caf539cd1087f7c36b9c4df271575e9aee49fde5 (diff) | |
| download | linux-5b4fc3882a649c9411dd0dcad2ddb78e911d340e.tar.gz linux-5b4fc3882a649c9411dd0dcad2ddb78e911d340e.tar.bz2 linux-5b4fc3882a649c9411dd0dcad2ddb78e911d340e.zip | |
sparc64: Make corrupted user stacks more debuggable.
Right now if we get a corrupted user stack frame we do a
do_exit(SIGILL) which is not helpful.
If under a debugger, this behavior causes the inferior process to
exit. So the register and other state cannot be examined at the time
of the event.
Instead, conditionally log a rate limited kernel log message and then
force a SIGSEGV.
With bits and ideas borrowed (as usual) from powerpc.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/kernel/process_64.c')
| -rw-r--r-- | arch/sparc/kernel/process_64.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index 6c086086ca8f..59eaf6227af1 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -36,6 +36,7 @@ #include <linux/sysrq.h> #include <linux/nmi.h> #include <linux/context_tracking.h> +#include <linux/signal.h> #include <linux/uaccess.h> #include <asm/page.h> @@ -521,7 +522,12 @@ static void stack_unaligned(unsigned long sp) force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp, 0, current); } -void fault_in_user_windows(void) +static const char uwfault32[] = KERN_INFO \ + "%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n"; +static const char uwfault64[] = KERN_INFO \ + "%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n"; + +void fault_in_user_windows(struct pt_regs *regs) { struct thread_info *t = current_thread_info(); unsigned long window; @@ -534,9 +540,9 @@ void fault_in_user_windows(void) do { struct reg_window *rwin = &t->reg_window[window]; int winsize = sizeof(struct reg_window); - unsigned long sp; + unsigned long sp, orig_sp; - sp = t->rwbuf_stkptrs[window]; + orig_sp = sp = t->rwbuf_stkptrs[window]; if (test_thread_64bit_stack(sp)) sp += STACK_BIAS; @@ -547,8 +553,16 @@ void fault_in_user_windows(void) stack_unaligned(sp); if (unlikely(copy_to_user((char __user *)sp, - rwin, winsize))) + rwin, winsize))) { + if (show_unhandled_signals) + printk_ratelimited(is_compat_task() ? + uwfault32 : uwfault64, + current->comm, current->pid, + sp, orig_sp, + regs->tpc, + regs->u_regs[UREG_I7]); goto barf; + } } while (window--); } set_thread_wsaved(0); @@ -556,8 +570,7 @@ void fault_in_user_windows(void) barf: set_thread_wsaved(window + 1); - user_exit(); - do_exit(SIGILL); + force_sig(SIGSEGV, current); } asmlinkage long sparc_do_fork(unsigned long clone_flags, |