On Tue, Feb 16, 2016 at 11:00 AM, Takashi Iwai <tiwai@xxxxxxx> wrote: > On Tue, 16 Feb 2016 10:41:54 +0100, > Dmitry Vyukov wrote: >> >> Hello, >> >> Here is a new one on 18558cae0272f8fd9647e69d3fec1565a7949865 >> (4.5-rc4). But need to note that sound become much more stable, I've >> seen only 2 of these over night. >> >> The following program causes list corruption: >> >> ------------[ cut here ]------------ >> WARNING: CPU: 2 PID: 12546 at lib/list_debug.c:62 __list_del_entry+0x10b/0x1e0() >> list_del corruption, ffff880063512388->next is LIST_POISON1 (dead000000000100) >> Modules linked in: >> CPU: 2 PID: 12546 Comm: a.out Not tainted 4.5.0-rc4+ #328 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >> ffffffff87b05080 ffff8800608b7a48 ffffffff82be46cf ffffffff81477fb8 >> fffffbfff0f60a10 ffff8800608b7ab8 ffff8800637d97c0 ffffffff86ad3780 >> 0000000000000009 000000000000003e ffff8800608b7a88 ffffffff81355139 >> Call Trace: >> [<ffffffff81355249>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:494 >> [<ffffffff82c4c36b>] __list_del_entry+0x10b/0x1e0 lib/list_debug.c:60 >> [<ffffffff82c4c44d>] list_del+0xd/0x70 lib/list_debug.c:86 >> [<ffffffff852c38e3>] delete_and_unsubscribe_port+0x1e3/0x2f0 >> sound/core/seq/seq_ports.c:545 >> [<ffffffff852c43fa>] clear_subscriber_list+0x15a/0x260 >> sound/core/seq/seq_ports.c:250 >> [<ffffffff852c456a>] port_delete+0x6a/0x1c0 sound/core/seq/seq_ports.c:266 >> [<ffffffff852c5242>] snd_seq_delete_all_ports+0x242/0x350 >> sound/core/seq/seq_ports.c:330 >> [<ffffffff852ae1cf>] seq_free_client1+0x2f/0x290 >> sound/core/seq/seq_clientmgr.c:272 >> [<ffffffff852ae495>] seq_free_client+0x65/0x160 >> sound/core/seq/seq_clientmgr.c:299 >> [<ffffffff852b118d>] snd_seq_release+0x4d/0xb0 >> sound/core/seq/seq_clientmgr.c:380 >> [<ffffffff817c3256>] __fput+0x236/0x780 fs/file_table.c:208 >> [<ffffffff817c3825>] ____fput+0x15/0x20 fs/file_table.c:244 >> [<ffffffff813b3100>] task_work_run+0x170/0x210 kernel/task_work.c:115 >> [< inline >] tracehook_notify_resume include/linux/tracehook.h:191 >> [<ffffffff810066b1>] exit_to_usermode_loop+0x1d1/0x210 >> arch/x86/entry/common.c:251 >> [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:282 >> [<ffffffff810084ea>] syscall_return_slowpath+0x2ba/0x340 >> arch/x86/entry/common.c:344 >> [<ffffffff866626e2>] int_ret_from_sys_call+0x25/0x9f >> arch/x86/entry/entry_64.S:281 >> ---[ end trace 4cad985f706f8ace ]--- > > Hm, this might be the remaining open race at deleting ports. > Please try the patch below. Yes, it fixes the crash for me. Tested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Thanks! > thanks, > > Takashi > > --- > diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c > index 921fb2bd8fad..fe686ee41c6d 100644 > --- a/sound/core/seq/seq_ports.c > +++ b/sound/core/seq/seq_ports.c > @@ -535,19 +535,22 @@ static void delete_and_unsubscribe_port(struct snd_seq_client *client, > bool is_src, bool ack) > { > struct snd_seq_port_subs_info *grp; > + struct list_head *list; > + bool empty; > > grp = is_src ? &port->c_src : &port->c_dest; > + list = is_src ? &subs->src_list : &subs->dest_list; > down_write(&grp->list_mutex); > write_lock_irq(&grp->list_lock); > - if (is_src) > - list_del(&subs->src_list); > - else > - list_del(&subs->dest_list); > + empty = list_empty(list); > + if (!empty) > + list_del_init(list); > grp->exclusive = 0; > write_unlock_irq(&grp->list_lock); > up_write(&grp->list_mutex); > > - unsubscribe_port(client, port, grp, &subs->info, ack); > + if (!empty) > + unsubscribe_port(client, port, grp, &subs->info, ack); > } > > /* connect two ports */ _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel