From 805035d70cd8637c169caf97800accdd267d1d8e Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Fri, 27 Nov 2015 14:53:32 +0000 Subject: [PATCH] [AArch64] Only check breakpoint alignment on inserting This patch fixes the GDB internal error on AArch64 when running watchpoint-fork.exp top?bt 15 internal_error (file=file@entry=0x79d558 "../../binutils-gdb/gdb/linux-nat.c", line=line@entry=4866, fmt=0x793b20 "%s: Assertion `%s' failed.") at ../../binutils-gdb/gdb/common/errors.c:51 #1 0x0000000000495bc4 in linux_nat_thread_address_space (t=, ptid=) at ../../binutils-gdb/gdb/linux-nat.c:4866 #2 0x00000000005db2c8 in delegate_thread_address_space (self=, arg1=) at ../../binutils-gdb/gdb/target-delegates.c:2447 #3 0x00000000005e8c7c in target_thread_address_space (ptid=) at ../../binutils-gdb/gdb/target.c:2727 #4 0x000000000054eef8 in get_thread_arch_regcache (ptid=..., gdbarch=0xad51e0) at ../../binutils-gdb/gdb/regcache.c:529 #5 0x000000000054efcc in get_thread_regcache (ptid=...) at ../../binutils-gdb/gdb/regcache.c:546 #6 0x000000000054f120 in get_thread_regcache_for_ptid (ptid=...) at ../../binutils-gdb/gdb/regcache.c:560 #7 0x00000000004a2278 in aarch64_point_is_aligned (is_watchpoint=0, addr=34168, len=2) at ../../binutils-gdb/gdb/nat/aarch64-linux-hw-point.c:122 #8 0x00000000004a2e68 in aarch64_handle_breakpoint (type=hw_execute, addr=34168, len=2, is_insert=0, state=0xae8880) at ../../binutils-gdb/gdb/nat/aarch64-linux-hw-point.c:465 #9 0x000000000048edf0 in aarch64_linux_remove_hw_breakpoint (self=, gdbarch=, bp_tgt=) at ../../binutils-gdb/gdb/aarch64-linux-nat.c:657 #10 0x00000000005da8dc in delegate_remove_hw_breakpoint (self=, arg1=, arg2=) at ../../binutils-gdb/gdb/target-delegates.c:492 #11 0x0000000000536a24 in bkpt_remove_location (bl=) at ../../binutils-gdb/gdb/breakpoint.c:13065 #12 0x000000000053351c in remove_breakpoint_1 (bl=0xb3fe70, is=is@entry=mark_inserted) at ../../binutils-gdb/gdb/breakpoint.c:4026 #13 0x000000000053ccc0 in detach_breakpoints (ptid=...) at ../../binutils-gdb/gdb/breakpoint.c:3930 #14 0x00000000005a3ac0 in handle_inferior_event_1 (ecs=0x7ffffff048) at ../../binutils-gdb/gdb/infrun.c:5042 After the fork, GDB will physically remove the breakpoints from the child process (in frame #14), but at that time, GDB doesn't create an inferior yet for child, but inferior_ptid is set to child's ptid (in frame #13). In aarch64_point_is_aligned, we'll get the regcache of current_lwp_ptid to determine if the current process is 32-bit or 64-bit, so the inferior can't be found, and the internal error is caused. I don't find a better fix other than not checking alignment on removing breakpoint. gdb: 2015-11-27 Yao Qi * nat/aarch64-linux-hw-point.c (aarch64_dr_state_remove_one_point): Don't assert on alignment. (aarch64_handle_breakpoint): Only check alignment when IS_INSERT is true. --- gdb/ChangeLog | 7 +++++++ gdb/nat/aarch64-linux-hw-point.c | 21 ++++++++++++++------- 2 files changed, 21 insertions(+), 7 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e883ffcd6e..54642e1a53 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2015-11-27 Yao Qi + + * nat/aarch64-linux-hw-point.c (aarch64_dr_state_remove_one_point): + Don't assert on alignment. + (aarch64_handle_breakpoint): Only check alignment when IS_INSERT + is true. + 2015-11-27 Yao Qi * aarch64-tdep.c (is_hfa): Rename to ... diff --git a/gdb/nat/aarch64-linux-hw-point.c b/gdb/nat/aarch64-linux-hw-point.c index dcbfa98c3b..466823a432 100644 --- a/gdb/nat/aarch64-linux-hw-point.c +++ b/gdb/nat/aarch64-linux-hw-point.c @@ -411,7 +411,6 @@ aarch64_dr_state_remove_one_point (struct aarch64_debug_reg_state *state, /* Set up state pointers. */ is_watchpoint = (type != hw_execute); - gdb_assert (aarch64_point_is_aligned (is_watchpoint, addr, len)); if (is_watchpoint) { num_regs = aarch64_num_wp_regs; @@ -460,13 +459,21 @@ aarch64_handle_breakpoint (enum target_hw_bp_type type, CORE_ADDR addr, int len, int is_insert, struct aarch64_debug_reg_state *state) { - /* The hardware breakpoint on AArch64 should always be 4-byte - aligned, but on AArch32, it can be 2-byte aligned. */ - if (!aarch64_point_is_aligned (0 /* is_watchpoint */ , addr, len)) - return -1; - if (is_insert) - return aarch64_dr_state_insert_one_point (state, type, addr, len); + { + /* The hardware breakpoint on AArch64 should always be 4-byte + aligned, but on AArch32, it can be 2-byte aligned. Note that + we only check the alignment on inserting breakpoint because + aarch64_point_is_aligned needs the inferior_ptid inferior's + regcache to decide whether the inferior is 32-bit or 64-bit. + However when GDB follows the parent process and detach breakpoints + from child process, inferior_ptid is the child ptid, but the + child inferior doesn't exist in GDB's view yet. */ + if (!aarch64_point_is_aligned (0 /* is_watchpoint */ , addr, len)) + return -1; + + return aarch64_dr_state_insert_one_point (state, type, addr, len); + } else return aarch64_dr_state_remove_one_point (state, type, addr, len); }