From: Joel Brobecker <brobecker@adacore.com>
To: Pedro Alves <palves@redhat.com>
Cc: gdb-patches@sourceware.org
Subject: Re: RFC: skip_inline_frames failed assertion resuming from breakpoint on LynxOS
Date: Thu, 20 Nov 2014 17:11:00 -0000 [thread overview]
Message-ID: <20141120171137.GT5774@adacore.com> (raw)
In-Reply-To: <546DBA9F.9060600@redhat.com>
Hi Pedro,
> > infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT, step=0)
> > infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
>
> trap_expected=1 indicates that GDB is about to step thread 142 _only_, leaving
> everything else stopped. Can you enable "set debug remote 1" as well?
Correct (we are single-stepping out of a breakpoint).
Here is the output with remote debugging:
| Continuing.
| infrun: clear_proceed_status_thread (Thread 126)
| infrun: clear_proceed_status_thread (Thread 147)
| infrun: clear_proceed_status_thread (Thread 134)
| infrun: clear_proceed_status_thread (Thread 135)
| infrun: clear_proceed_status_thread (Thread 133)
| infrun: clear_proceed_status_thread (Thread 136)
| infrun: clear_proceed_status_thread (Thread 127)
| infrun: clear_proceed_status_thread (Thread 129)
| infrun: clear_proceed_status_thread (Thread 128)
| infrun: clear_proceed_status_thread (Thread 130)
| infrun: clear_proceed_status_thread (Thread 132)
| infrun: clear_proceed_status_thread (Thread 141)
| infrun: clear_proceed_status_thread (Thread 131)
| infrun: clear_proceed_status_thread (Thread 137)
| infrun: clear_proceed_status_thread (Thread 138)
| infrun: clear_proceed_status_thread (Thread 139)
| infrun: clear_proceed_status_thread (Thread 140)
| infrun: clear_proceed_status_thread (Thread 142)
| infrun: clear_proceed_status_thread (Thread 143)
| infrun: clear_proceed_status_thread (Thread 144)
| infrun: clear_proceed_status_thread (Thread 145)
| infrun: clear_proceed_status_thread (Thread 146)
| infrun: clear_proceed_status_thread (Thread 125)
| infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT, step=0)
| infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
| Sending packet: $Hg8e#4c...Packet received: OK
| Sending packet: $m10684838,4#73...Packet received: 4ba1db21
| Sending packet: $QPassSignals:#f3...Packet received: OK
| Sending packet: $vCont;s:8e#8f...infrun: wait_for_inferior ()
| Packet received: T2e01:3a440910;40:10a187f4;thread:92;
| infrun: target_wait (-1, status) =
| infrun: 42000 [Thread 146],
| infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_34
| infrun: infwait_normal_state
| infrun: TARGET_WAITKIND_STOPPED
| infrun: stop_pc = 0x10a187f4
| infrun: context switch
| infrun: Switching context from Thread 142 to Thread 146
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $g#67...Packet received: 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
| infrun: random signal (GDB_SIGNAL_REALTIME_34)
| Sending packet: $T8e#f1...Packet received: OK
| infrun: switching back to stepped thread
| infrun: Switching context from Thread 146 to Thread 142
| Sending packet: $Hg8e#4c...Packet received: OK
| Sending packet: $g#67...Packet received: 103422e83a8948e02003b21000000000000000000000000900000008000000090000000020037a301068480800000000220000420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402001791c3a89499000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000106848380002f43042000042103422e81068480820000000fff80000
| infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
| Sending packet: $m10684838,4#73...Packet received: 4ba1db21
| Sending packet: $vCont;s:8e#8f...infrun: prepare_to_wait
| Packet received: T2f01:3a55b910;40:10a187f4;thread:91;
| infrun: target_wait (-1, status) =
| infrun: 42000 [Thread 145],
| infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_35
| infrun: infwait_normal_state
| infrun: TARGET_WAITKIND_STOPPED
| infrun: stop_pc = 0x10a187f4
| infrun: context switch
| infrun: Switching context from Thread 142 to Thread 145
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $g#67...Packet received: 000000c33a55b9102003b21020ed76b03a55b8d800000000000001fe000000010000000120ed76b0100703ac00000000280000020000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402000e6883a55b9100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010a187f40000f030280000081099d6dc109db33400000000fff80000
| infrun: random signal (GDB_SIGNAL_REALTIME_35)
| Sending packet: $T8e#f1...Packet received: OK
| infrun: switching back to stepped thread
| infrun: Switching context from Thread 145 to Thread 142
| Sending packet: $Hg8e#4c...Packet received: OK
| Sending packet: $g#67...Packet received: 103422e83a8948e02003b21000000000000000000000000900000008000000090000000020037a301068480800000000220000420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402001791c3a89499000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000106848380002f43042000042103422e81068480820000000fff80000
| infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
| Sending packet: $m10684838,4#73...Packet received: 4ba1db21
| Sending packet: $vCont;s:8e#8f...infrun: prepare_to_wait
| Packet received: T3001:3a65e910;40:10a187f4;thread:90;
| infrun: target_wait (-1, status) =
| infrun: 42000 [Thread 144],
| infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_36
| infrun: infwait_normal_state
| infrun: TARGET_WAITKIND_STOPPED
| infrun: stop_pc = 0x10a187f4
| infrun: context switch
| infrun: Switching context from Thread 142 to Thread 144
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $g#67...Packet received: 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
| infrun: random signal (GDB_SIGNAL_REALTIME_36)
| Sending packet: $T8e#f1...Packet received: OK
| infrun: switching back to stepped thread
| infrun: Switching context from Thread 144 to Thread 142
| Sending packet: $Hg8e#4c...Packet received: OK
| Sending packet: $g#67...Packet received: 103422e83a8948e02003b21000000000000000000000000900000008000000090000000020037a301068480800000000220000420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402001791c3a89499000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000106848380002f43042000042103422e81068480820000000fff80000
| infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
| Sending packet: $m10684838,4#73...Packet received: 4ba1db21
| Sending packet: $vCont;s:8e#8f...infrun: prepare_to_wait
| Packet received: T3101:3a791910;40:10a187f4;thread:8f;
| infrun: target_wait (-1, status) =
| infrun: 42000 [Thread 143],
| infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_37
| infrun: infwait_normal_state
| infrun: TARGET_WAITKIND_STOPPED
| infrun: stop_pc = 0x10a187f4
| infrun: context switch
| infrun: Switching context from Thread 142 to Thread 143
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $g#67...Packet received: 000000c33a7919102003b21020ed76c03a7918d800000000000002123a7919905448524420ed76c0b07da7b020f07728200000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402000e6883a7919100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010a187f40000f030280000081099d6dc109db33400000000fff80000
| infrun: random signal (GDB_SIGNAL_REALTIME_37)
| Sending packet: $T8e#f1...Packet received: OK
| infrun: switching back to stepped thread
| infrun: Switching context from Thread 143 to Thread 142
| Sending packet: $Hg8e#4c...Packet received: OK
| Sending packet: $g#67...Packet received: 103422e83a8948e02003b21000000000000000000000000900000008000000090000000020037a301068480800000000220000420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020f071402001791c3a89499000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000106848380002f43042000042103422e81068480820000000fff80000
| infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
| Sending packet: $m10684838,4#73...Packet received: 4ba1db21
| Sending packet: $vCont;s:8e#8f...infrun: prepare_to_wait
| Packet received: T2e01:3a440910;40:10a187f4;thread:92;
| infrun: target_wait (-1, status) =
| infrun: 42000 [Thread 146],
| infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_34
| infrun: infwait_normal_state
| infrun: TARGET_WAITKIND_STOPPED
| infrun: stop_pc = 0x10a187f4
| infrun: context switch
| infrun: Switching context from Thread 142 to Thread 146
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| Sending packet: $m10a187f0,4#c5...Packet received: 44000002
| ../../src/gdb/inline-frame.c:339: internal-error: skip_inline_frames: Assertion `find_inline_frame_state (ptid) == NULL' failed.
> > infrun: wait_for_inferior ()
> > infrun: target_wait (-1, status) =
> > infrun: 42000 [Thread 146],
> > infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_34
>
> So how come we see an event for thread 146? That thread shouldn't
> have been resumed, so GDB shouldn't be getting an event for it.
>
> This is sounding like a bug in the target.
I thought about this too, and there might be a ptrace request
I can use to absolutely limit the resumption to the one thread.
I say "might" because only testing will show if the request is
supported, and works, on all versions of LynxOS.
But I have always been relunctant to do so for 2 reasons [1]:
- It affects the program's scheduling;
- Can the program lock up if we're trying to single-step
a thread that's blocked?
Also, what made me consider this change independently of the questions
above is that it seems to me that it the situation we are facing here
seems to be easily handled. So, to avoid headaches from other "buggy"
targets, containing this situation seemed friendlier. Don't we also
have other targets that don't have the capability to resume one single
thread?
--
Joel
[1]: I realize that this opens the door for other threads executing
this instruction without triggering a breakpoint. I can't
explain why I am more concerned by scheduling interference
than the probability of missing a breakpoint. I may bite the
bullet at some point...
next prev parent reply other threads:[~2014-11-20 17:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 5:11 Joel Brobecker
2014-11-20 5:12 ` Joel Brobecker
2014-11-20 9:55 ` Pedro Alves
2014-11-20 17:11 ` Joel Brobecker [this message]
2014-11-21 10:43 ` Pedro Alves
2014-12-13 15:46 ` Joel Brobecker
2014-12-15 13:11 ` Pedro Alves
2014-12-15 14:58 ` Joel Brobecker
2014-12-15 16:01 ` Pedro Alves
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