Re: [Qemu-devel] [5187] Use signalfd() to work around signal/select race

[Laurent Vivier <Laurent.Vivier@bull.net>]

Le mercredi 10 septembre 2008 à 15:45 +0000, Anthony Liguori a écrit :
> Revision: 5187
>           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5187
> Author:   aliguori
> Date:     2008-09-10 15:45:19 +0000 (Wed, 10 Sep 2008)
> 
> Log Message:
> -----------
> Use signalfd() to work around signal/select race

This commit breaks qemu-nbd:

# ./qemu-nbd --port 1024 --persistent ../disk.qcow2 
generates "Bus error" when I connect the client:
# ./x86_64-softmmu/qemu-system-x86_64 -hda ../etch64.qcow2 -hdb
nbd:localhost:1024

* gdb output:

Program received signal SIGBUS, Bus error.
[Switching to Thread 0x7f3accdf76e0 (LWP 13146)]
qemu_aio_wait () at block-raw-posix.c:541
541	        FD_SET(aio_sig_fd, &rdfds);
(gdb) bt
#0  qemu_aio_wait () at block-raw-posix.c:541
#1  0x0000000000406245 in bdrv_read_em (bs=0x0,
sector_num=140736764918416, 
    buf=0x8000000000000000 <Address 0x8000000000000000 out of bounds>, 
    nb_sectors=0) at block.c:1289
#2  0x000000000040437a in nbd_trip (bs=0x622010, csock=8,
size=6442450944, 
    dev_offset=0, offset=0x7fffd4e13c78, readonly=false, 
    data=0x7f3acccd5200 "�H\220м", data_size=1048576) at nbd.c:573
#3  0x0000000000402d11 in main (argc=1, argv=0x1) at qemu-nbd.c:444

Laurent
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----------------- Laurent.Vivier@bull.net  ------------------
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