Yesterday I updated Cygwin using setup-x86_64 to the latest non test release,
and bash —login would no longer start.
It turns out bash won’t start for me when a .profile runs a sub-command.
This is highlighted by:-
gdb bash
dll cygwin1.dll
b timegm
run
bash-5.2$ echo foo
foo
bash-5.2$ a=`echo foo`
Program received signal SIGSEGV, Segmentation fault.
0x00007ffa5cb3ce31 in timegm () from D:\cygwin64\bin\cygwin1.dll
(gdb)
...
bash-5.2$ a=`xxx`
bash: xxx: command not found
Program received signal SIGSEGV, Segmentation fault.
0x00007ffa5cb3ce31 in timegm () from D:\cygwin64\bin\cygwin1.dll
(gdb)
uname -a CYGWIN_NT-10.0-26100 garyl 3.7.0-0.98.gb39b510c1ce6.x86_64
2025-05-18 15:52 UTC x86_64 Cygwin
Any format of a=$(echo bar) or a=`echo bar` causes a segfault, other than that
bash runs happily and runs commands.
My last working version was quite old
uname -a
CYGWIN_NT-10.0-26100 garyl 3.7.0-0.98.gb39b510c1ce6.x86_64 2025-05-18
15:52 UTC x86_64 Cygwin
I have restored a copy of this and it works fine.
I should day I ran bash under strace , it does the same thing, see [STRACE
SNIPPET].
I have also tried this with some variants of
bash
5.2.221-1
4.4-12-3
cygwin
3.5.5-1
3.6.1-1
3.7.0-0.98....
But they all fail in the same way.
I am at a loss as to how to dig further because gdb doesn’t seem to want to go
near timegm and I can’t see anything in the strace output that seems to point
to anything useful.
Can anyone help?
Regards
Gary
[STRACE SNIPPET]
326 12064632 [sig] bash 915 sigpacket::process: returning -1
419 12065051 [main] bash 915 proc_subproc: finished processing
terminated/stopped child
381 12065432 [main] bash 915 proc_subproc: returning 1
282 12065714
[main] bash 915 wait4: 0 = cygwait (...)
197 12065911 [main] bash 915 wait4: 920 = wait4(-1, 0x0, 10, 0x0)
364 12066275 [main] bash 915 set_signal_mask: setmask 80000, newmask 0,
mask_bits 80000 349 12066624
[main] bash 915 sig_send: sendsig 0x144, pid 915, signal -71, its_me 1
375 12066999 [main] bash 915 sig_send: wakeup 0x314
300 12067299
[main] bash 915 sig_send: Waiting for pack.wakeup 0x314
14426 12081725 [sig] bash 915 sigpacket::process: signal 20 processing
295 12082020 [sig] bash 915 init_cygheap::find_tls: sig 20
248 12082268 [sig] bash 915 sigpacket::process: using tls 0x7FFFFCE00
665 12082933 [sig]
bash 915 sigpacket::process: signal 20, signal handler 0x10042CB90
281 12083214 [sig] bash 915 sigpacket::setup_handler: controlled interrupt.
stackptr 0x7FFFFE2B0, stack 0x7FFFFE2A8, stackptr[-1] 0x10042DB0B
380 12083594 [sig] bash 915 proc_subproc: args: 4, 1
282 12083876 [sig]
bash 915 proc_subproc: clear waiting threads
280 12084156 [sig] bash 915 proc_subproc: finished clearing
278 12084434 [sig] bash 915 proc_subproc: returning 1
280 12084714 [sig]
bash 915 _cygtls::interrupt_setup: armed signal_arrived 0x2D0, signal 20
283 12084997 [sig] bash 915 sigpacket::setup_handler: signal 20 delivered
281 12085278 [sig]
bash 915 sigpacket::process: returning 1
383 12085661 [sig] bash 915 wait_sig: signalling pack.wakeup 0x314
332 12085993 [main] bash 915 sig_send: returning 0x0 from sending signal -71
282 12086275 [main] bash 915 sigprocmask: 0 = sigprocmask (0, 0x7FFFFC2D0,
0x0) --- Process 14168
(pid: 915), exception c0000005 at 00007ffa2029ce31
--- Process 14168 (pid: 915) thread 3880 exited with status 0xc0000005
--- Process 14168 (pid: 915) thread 6164 exited with status 0xc0000005
--- Process 14168 (pid: 915) thread 23756 exited with status 0xc0000005
--- Process 14168
(pid: 915) thread 3312 exited with status 0xc0000005
--- Process 14168 (pid: 915) thread 5208 exited with status 0xc0000005
--- Process 14168
thread 23072 exited with status 0xc0000005
--- Process 14168 thread 17704 exited with status 0xc0000005
--- Process 14168
thread 13696 exited with status 0xc0000005
--- Process 14168 exited with status 0xc0000005
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