[Qemu-devel] [PATCH] readline: don't free completions in readline_free()

[Greg Kurz]

Since commit e5dc1a6c6c43, QEMU aborts on exit if completion was used
in the monitor:

*** Error in `obj/ppc64-softmmu/qemu-system-ppc64': double free or
 corruption (fasttop): 0x00000100331069d0 ***

#0  0x00007ffff267eff0 in raise () from /lib64/libc.so.6
#1  0x00007ffff268136c in abort () from /lib64/libc.so.6
#2  0x00007ffff26c6b48 in __libc_message () from /lib64/libc.so.6
#3  0x00007ffff26d69fc in free () from /lib64/libc.so.6
#4  0x00007ffff28cb794 in g_free () from /lib64/libglib-2.0.so.0
#5  0x00000000106230e4 in readline_free (rs=0x11223e60) at
 /home/greg/Work/qemu/qemu-spapr/util/readline.c:514
#6  0x0000000010074cc4 in monitor_data_destroy (mon=0x1121c9f0) at
 /home/greg/Work/qemu/qemu-spapr/monitor.c:586
#7  0x000000001007bcc8 in monitor_cleanup () at
 /home/greg/Work/qemu/qemu-spapr/monitor.c:4125
#8  0x0000000010291274 in main (argc=<optimized out>,
 argv=<optimized out>, envp=<optimized out>) at
 /home/greg/Work/qemu/qemu-spapr/vl.c:4795

Completion strings are not persistent accross completions (why would
they?). They are allocated under readline_completion(), which already
takes care of freeing them before returning.

Maybe all completion related bits should be moved out of ReadLineState
to a dedicated structure ?

In the meantime, let's drop the offending lines from readline_free()
to fix the crash.

Signed-off-by: Greg Kurz <address@hidden>
---
 util/readline.c |    3 ---
 1 file changed, 3 deletions(-)

diff --git a/util/readline.c b/util/readline.c
index 24ec839854cf..ec91ee0fea6f 100644
--- a/util/readline.c
+++ b/util/readline.c
@@ -510,9 +510,6 @@ void readline_free(ReadLineState *rs)
     for (i = 0; i < READLINE_MAX_CMDS; i++) {
         g_free(rs->history[i]);
     }
-    for (i = 0; i < READLINE_MAX_COMPLETIONS; i++) {
-        g_free(rs->completions[i]);
-    }
     g_free(rs);
 }