Bug#1125713: apache2: Upgrade to 2.4.66-1~deb12u1 produces zombie PHP processes with FastCGI

Bastien Roucaries <[email protected]> Wed, 21 Jan 2026 12:13:07 +0100

Newsgroups	gmane.linux.debian.devel.apache
Message-ID	<2817755.mvXUDI8C0e__28314.7234631301$1768994143$gmane$org@debian-ei>

Le mercredi 21 janvier 2026, 11:49:35 heure normale d’Europe centrale Thomas Stangner a écrit :
> Hi,
> 
> I also ran into this problem and was able to generate coredumps to debug 
> the issue.
> 
> The zombie FCGI processes are caused by segfaulting parent Apache2 
> processes:
> 
> [Wed Jan 21 08:15:04.609766 2026] [core:notice] [pid 4996:tid 4996] 
> AH00052: child pid 36382 exit signal Segmentation fault (11)
> [Wed Jan 21 08:40:04.282658 2026] [core:notice] [pid 4996:tid 4996] 
> AH00052: child pid 85420 exit signal Segmentation fault (11)
> [Wed Jan 21 08:54:05.207724 2026] [core:notice] [pid 4996:tid 4996] 
> AH00052: child pid 22762 exit signal Segmentation fault (11)
> 
> The father Apache2 process gets terminated by the segfault and the 
> previously spawned FCGI child processes end up as zombies, because 
> nobody does a wait()/waitpid() on them.
> 
> The segfaults are caused by a bug in mod_http2:
> 
> ---------8<--------8<----------
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0  c1_purge_streams (m=0x7fd5f77fb738) at ./modules/http2/h2_mplx.c:606
> [Current thread is 1 (Thread 0x7fd5e27fc6c0 (LWP 79820))]
> (gdb) bt full
> #0  c1_purge_streams (m=0x7fd5f77fb738) at ./modules/http2/h2_mplx.c:606
>          stream = 0x7fd5ff5bc0a0
>          i = 1
> #1  0x00007fd602eb1fe0 in h2_mplx_c1_poll (m=0x7fd5f77fb738, 
> timeout=timeout@entry=0, 
> on_stream_input=on_stream_input@entry=0x7fd602eb7230 <on_stream_input>, 
> on_stream_output=on_stream_output@entry=0x7fd602eb70f0 
> <on_stream_output>, on_ctx=on_ctx@entry=0x7fd5f77fb0a0) at 
> ./modules/http2/h2_mplx.c:659
>          rv = <optimized out>
> #2  0x00007fd602ebb1bc in h2_session_process (session=0x7fd5f77fb0a0, 
> async=0, pkeepalive=pkeepalive@entry=0x7fd5e27fbd14) at 
> ./modules/http2/h2_session.c:2013
>          status = 0
>          c = 0x7fd5f78042c8
>          rv = <optimized out>
>          mpm_state = 1
>          trace = 0
> #3  0x00007fd602ea481c in h2_c1_run (c=0x7fd5f78042c8) at 
> ./modules/http2/h2_c1.c:132
>          status = <optimized out>
>          mpm_state = 0
>          keepalive = 0
>          conn_ctx = 0x7fd5f783a3b0
> #4  0x00005623928a4030 in ap_run_process_connection 
> (c=c@entry=0x7fd5f78042c8) at ./server/connection.c:42
>          pHook = <optimized out>
>          n = 4
>          rv = -1
> ---------8<--------8<----------
> 
> An update to mod_http 2.0.37 resolves the problem (via this upstream patch):
> 
> https://github.com/apache/httpd/commit/e41e84e08e6186460e77a8357b5d5c571d33bd76
> 
> So I suggest cherry-picking this commit from the 2.4.x branch and 
> patching/updating mod_http2 from 2.0.35 to 2.0.37.
Could you test apache2 experimental ?
> 
> Cheers,
> Thomas
>

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