From a911d87ad714cbfbbc5c5752cb8b445a7e70196c Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Wed, 13 Jan 2016 10:40:33 +0000 Subject: Fix PR19388: Can't access $_siginfo in breakpoint (catch signal) condition This commit merges both the registers and $_siginfo "thread running/executing" checks into a single function. Accessing $_siginfo from a "catch signal" breakpoint condition doesn't work. The condition always fails with "Selected thread is running": (gdb) catch signal Catchpoint 3 (standard signals) (gdb) condition $bpnum $_siginfo.si_signo == 5 (gdb) continue Continuing. Error in testing breakpoint condition: Selected thread is running. Catchpoint 3 (signal SIGUSR1), 0x0000003615e35877 in __GI_raise (sig=10) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 56 return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig); (gdb) When accessing the $_siginfo object, we check whether the thread is marked running (external/public) state and refuse the access if so. This is so "print $_siginfo" at the prompt fails nicelly when the current thread is running. While evaluating breakpoint conditionals, we haven't decided yet whether the thread is going to stop, so is_running still returns true, and we thus always error out. Evaluating an expression that requires registers access is really conceptually the same -- we could think of $_siginfo as a pseudo register. However, in that case we check whether the thread is marked executing (internal/private state), not running (external/public state). Changing the $_siginfo validation to check is_executing as well fixes the bug in question. Note that checking is_executing is not fully correct, not even for registers. See PR 19389. However, I think this is the lesser of two evils and ends up as an improvement. We at least now have a single place to fix. Tested on x86_64 GNU/Linux. gdb/ChangeLog: 2016-01-13 Pedro Alves PR breakpoints/19388 * frame.c (get_current_frame): Use validate_registers_access. * gdbthread.h (validate_registers_access): Declare. * infrun.c (validate_siginfo_access): Delete. (siginfo_value_read, siginfo_value_write): Use validate_registers_access. * thread.c (validate_registers_access): New function. gdb/testsuite/ChangeLog: 2016-01-13 Pedro Alves PR breakpoints/19388 * gdb.base/catch-signal-siginfo-cond.c: New file. * gdb.base/catch-signal-siginfo-cond.exp: New file. --- gdb/frame.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'gdb/frame.c') diff --git a/gdb/frame.c b/gdb/frame.c index 00a5ebc..48c9b33 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -1473,14 +1473,7 @@ get_current_frame (void) error (_("No memory.")); /* Traceframes are effectively a substitute for the live inferior. */ if (get_traceframe_number () < 0) - { - if (ptid_equal (inferior_ptid, null_ptid)) - error (_("No selected thread.")); - if (is_exited (inferior_ptid)) - error (_("Invalid selected thread.")); - if (is_executing (inferior_ptid)) - error (_("Target is executing.")); - } + validate_registers_access (); if (current_frame == NULL) { -- cgit v1.1