BUG/MINOR: stream: protect stream_dump() against incomplete streams
If a stream is interrupted during its initialization by a panic signal
and tries to dump itself, it may cause a crash during the dump due to
scf and/or scb not being fully initialized. This may also happen while
releasing an endpoint to attach a new one. The effect is that instead
of dying on an abort, the process dies on a segv. This race is ultra-
rare but totally possible. E.g:
#0 se_fl_test (test=1, se=0x0) at include/haproxy/stconn.h:98
#1 sc_ep_test (test=1, sc=0x7ff8d5cbd560) at include/haproxy/stconn.h:148
#2 sc_conn (sc=0x7ff8d5cbd560) at include/haproxy/stconn.h:223
#3 stream_dump (buf=buf@entry=0x7ff9507e7678, s=0x7ff4c40c8800, pfx=pfx@entry=0x55996c558cb3 ' ' <repeats 13 times>, eol=eol@entry=10 '\n') at src/stream.c:2840
#4 0x000055996c493b42 in ha_task_dump (buf=buf@entry=0x7ff9507e7678, task=<optimized out>, pfx=pfx@entry=0x55996c558cb3 ' ' <repeats 13 times>) at src/debug.c:328
#5 0x000055996c493edb in ha_thread_dump_one (thr=thr@entry=18, from_signal=from_signal@entry=0) at src/debug.c:227
#6 0x000055996c493ff1 in ha_thread_dump (buf=buf@entry=0x7ff9507e7678, thr=thr@entry=18) at src/debug.c:270
#7 0x000055996c494257 in ha_panic () at src/debug.c:430
#8 ha_panic () at src/debug.c:411
(...)
#23 0x000055996c341fe8 in ssl_sock_close (conn=<optimized out>, xprt_ctx=0x7ff8dcae3880) at src/ssl_sock.c:6699
#24 0x000055996c397648 in conn_xprt_close (conn=0x7ff8c297b0c0) at include/haproxy/connection.h:148
#25 conn_full_close (conn=0x7ff8c297b0c0) at include/haproxy/connection.h:192
#26 h1_release (h1c=0x7ff8c297b3c0) at src/mux_h1.c:1074
#27 0x000055996c39c9f0 in h1_detach (sd=<optimized out>) at src/mux_h1.c:3502
#28 0x000055996c474de4 in sc_detach_endp (scp=scp@entry=0x7ff9507e3148) at src/stconn.c:375
#29 0x000055996c4752a5 in sc_reset_endp (sc=<optimized out>, sc@entry=0x7ff8d5cbd560) at src/stconn.c:475
Note that this cannot happen on "show sess" since a stream never leaves
process_stream in such an uninitialized state, thus it's really only the
crash dump that may cause this.
It should be backported to 2.8.
(cherry picked from commit e64bccab20121beadb2ba862e48db294595d0546)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed