At Mon, 15 Oct 2012 19:41:40 +0200, Matthieu CASTET wrote:
Hi Takashi,
Takashi Iwai a écrit :
At Fri, 12 Oct 2012 17:42:19 +0200, Matthieu CASTET wrote:
Hi,
Takashi Iwai a écrit :
[Added Daniel and Clemens in the loop]
I don't think this is needed.
So... the below is a quick hack I did without testing at all. Hopefully this can give some advance.
Thanks for the quick patch.
The patch didn't apply cleany of linus tree, of which tree is based your patch ?
Did you try the second one? The second one covers races in more places.
The only uncovered place is the autosuspend stuff in mixer.c (for PCM, it's used only in open/close, so it's no problem). I'll fix it later.
I didn't have time to test your latest patches : I will test them tomorrow. On which git tree are they based ? gregkh/usb.git ?
3.7-rc1.
But I believe I found other races in the alsa char device handling. With the attached patch, if you disconnect the usb audio device between "msleep o" and "msleep o+", you will free the card resource (snd_card_do_free) and then use it [1].
I did in in snd_ctl_open, but the same thing could be done in snd_pcm_open, ...
OK, we'd need a generic open/close protection. For PCM, there is already a fix in my last patchset, so it should work, but for other devices, the paths are still uncovered.
Takashi
Matthieu
[1] [ 30.768341] Alignment trap: not handling instruction e1960f9f at [<c0087ba4>] [ 30.775878] Unhandled fault: alignment exception (0x001) at 0x6b6b6c6f [ 30.782775] Internal error: : 1 [#1] SMP ARM [ 30.787292] Modules linked in: [ 30.790557] CPU: 0 Tainted: G W (3.6.0-03888-g9c0226d-dirty #25) [ 30.798187] PC is at __lock_acquire.clone.19+0x164/0xd40 [ 30.803802] LR is at lock_acquire+0x5c/0x70 [ 30.808227] pc : [<c0087ba8>] lr : [<c0088d54>] psr: 20000093 [ 30.808227] sp : cd727c70 ip : 00000001 fp : cd727ccc [ 30.820343] r10: c05c3994 r9 : c328c218 r8 : 6b6b6b6b [ 30.825866] r7 : cd74f640 r6 : 6b6b6c6f r5 : c05a4d5c r4 : cd726000 [ 30.832763] r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : c328c218 [ 30.839660] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user [ 30.847290] Control: 10c5387d Table: 8329c019 DAC: 00000015 [ 30.853363] Process arecord (pid: 635, stack limit = 0xcd7262f8) [ 30.859680] Stack: (0xcd727c70 to 0xcd728000) [ 30.864288] 7c60: 000000ec 00000000 c059ce68 00000001 [ 30.872955] 7c80: 00000000 c05c2cc0 00000009 c059ce38 60000013 00000004 cd727d14 cd727ca8 [ 30.881591] 7ca0: c00455b0 00000000 cd726000 60000013 cd74f640 c09c7d70 00000024 c3297440 [ 30.890228] 7cc0: cd727cfc cd727cd0 c0088d54 c0087a50 00000000 00000000 c02e3984 00000000 [ 30.898864] 7ce0: c328c208 00000001 c318cf40 c328c208 cd727d24 cd727d00 c03d8274 c0088d04 [ 30.907501] 7d00: 00000001 00000000 c02e3984 c32c7a48 c328c000 c32c7a48 cd727d44 cd727d28 [ 30.916107] 7d20: c02e3984 c03d824c c32c7a48 c328c000 00000000 07400000 cd727d64 cd727d48 [ 30.924774] 7d40: c02e68cc c02e3940 c04042d0 c32c7a48 c3291b20 07400000 cd727d8c cd727d68 [ 30.933380] 7d60: c02e3494 c02e6868 c3291b20 c32c7a48 cf9f83c0 00000000 c00f18c8 00000000 [ 30.942047] 7d80: cd727db4 cd727d90 c00f1960 c02e33f8 c00eedcc 00000000 c32c7a48 c3291b20 [ 30.950683] 7da0: c32c7a50 00000001 cd727ddc cd727db8 c00eb8b0 c00f18d4 cd727ea0 cd727f60 [ 30.959320] 7dc0: 00000000 00000000 cd727e98 00000000 cd727df4 cd727de0 c00eb96c c00eb6ec [ 30.967956] 7de0: cd727ea0 cd727ee0 cd727e6c cd727df8 c00fb974 c00eb950 cd727e6c cd727e08 [ 30.976593] 7e00: c00f8bd4 c00f8b1c c00f97fc 00000000 cd727ee0 00000001 00000000 cd727ee8 [ 30.985229] 7e20: 00000000 00000000 cf737178 c32c7a48 00000000 00000000 c3291b20 cd67f848 [ 30.993865] 7e40: 00000020 cd727ee0 c32c7a48 cd727f60 cd727e98 00000000 cd727ea0 cd726000 [ 31.002502] 7e60: cd727ed4 cd727e70 c00fc028 c00fb39c cd727ea0 cd727e80 00000000 c32cad64 [ 31.011138] 7e80: cd74f640 00000000 cd74f968 00000000 00000004 00000000 cf815e58 cf74a8f8 [ 31.019775] 7ea0: 00000000 00000000 cd726000 cd727f60 00000001 ffffff9c cfb07000 ffffff9c [ 31.028411] 7ec0: cd726000 00000000 cd727f54 cd727ed8 c00fc730 c00fbf84 00000041 00000000 [ 31.037048] 7ee0: cf815e58 cf74a8f8 35c12985 00000009 cfb07009 cd727e30 00000000 cf4fcb38 [ 31.045684] 7f00: c3291b20 00000101 00000008 00000000 00000000 cd773e98 cd727f54 cd727f28 [ 31.054321] 7f20: c0109814 c03d8818 00000000 cfb07000 00000000 00026150 cfb07000 00000000 [ 31.062957] 7f40: 00000003 00000001 cd727f94 cd727f58 c00ec7bc c00fc708 00000000 cd726000 [ 31.071594] 7f60: 00000000 00000000 00000024 00000100 becb28da b6eef8a0 00026150 00000005 [ 31.080261] 7f80: c0014728 00000000 cd727fa4 cd727f98 c00ec880 c00ec6d8 00000000 cd727fa8 [ 31.088897] 7fa0: c00145a0 c00ec864 becb28da b6eef8a0 becb28da 00000000 becb28ec ffffffff [ 31.097534] 7fc0: becb28da b6eef8a0 00026150 00000005 00000001 0001c3b8 000260b8 ffffffff [ 31.106170] 7fe0: 00000000 becb28d8 b6ea8c10 b6dc078c 60000010 becb28da de10c4ff be918a5f [ 31.114807] Backtrace: [ 31.117401] [<c0087a44>] (__lock_acquire.clone.19+0x0/0xd40) from [<c0088d54>] (lock_acquire+0x5c/0x70) [ 31.127349] [<c0088cf8>] (lock_acquire+0x0/0x70) from [<c03d8274>] (_raw_spin_lock+0x34/0x44) [ 31.136322] r7:c328c208 r6:c318cf40 r5:00000001 r4:c328c208 [ 31.142364] [<c03d8240>] (_raw_spin_lock+0x0/0x44) from [<c02e3984>] (snd_card_file_add+0x50/0xc0) [ 31.151824] r5:c32c7a48 r4:c328c000 [ 31.155639] [<c02e3934>] (snd_card_file_add+0x0/0xc0) from [<c02e68cc>] (snd_ctl_open+0x70/0x190) [ 31.164978] r7:07400000 r6:00000000 r5:c328c000 r4:c32c7a48 [ 31.170989] [<c02e685c>] (snd_ctl_open+0x0/0x190) from [<c02e3494>] (snd_open+0xa8/0x1a0) [ 31.179595] r7:07400000 r6:c3291b20 r5:c32c7a48 r4:c04042d0 [ 31.185638] [<c02e33ec>] (snd_open+0x0/0x1a0) from [<c00f1960>] (chrdev_open+0x98/0x160) [ 31.194183] [<c00f18c8>] (chrdev_open+0x0/0x160) from [<c00eb8b0>] (do_dentry_open.clone.18+0x1d0/0x264) [ 31.204193] r7:00000001 r6:c32c7a50 r5:c3291b20 r4:c32c7a48 [ 31.210205] [<c00eb6e0>] (do_dentry_open.clone.18+0x0/0x264) from [<c00eb96c>] (finish_open+0x28/0x40) [ 31.220062] [<c00eb944>] (finish_open+0x0/0x40) from [<c00fb974>] (do_last.clone.40+0x5e4/0xbe8) [ 31.229309] r4:cd727ee0 r3:cd727ea0 [ 31.233123] [<c00fb390>] (do_last.clone.40+0x0/0xbe8) from [<c00fc028>] (path_openat+0xb0/0x488) [ 31.242401] [<c00fbf78>] (path_openat+0x0/0x488) from [<c00fc730>] (do_filp_open+0x34/0x88) [ 31.251190] [<c00fc6fc>] (do_filp_open+0x0/0x88) from [<c00ec7bc>] (do_sys_open+0xf0/0x18c) [ 31.260009] r7:00000001 r6:00000003 r5:00000000 r4:cfb07000 [ 31.266021] [<c00ec6cc>] (do_sys_open+0x0/0x18c) from [<c00ec880>] (sys_open+0x28/0x2c) [ 31.274475] [<c00ec858>] (sys_open+0x0/0x2c) from [<c00145a0>] (ret_fast_syscall+0x0/0x30) [ 31.283203] Code: e3580000 0affffbe e2886f41 e1960f9f (e2800001) [ 31.289642] ---[ end trace e749a1146c99522c ]--- [ 31.294525] Kernel panic - not syncing: Fatal exception [2 diff <text/plain (base64)>] diff --git a/sound/core/control.c b/sound/core/control.c index 2487a6b..34c80d4 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -45,6 +45,7 @@ static LIST_HEAD(snd_control_ioctls); static LIST_HEAD(snd_control_compat_ioctls); #endif
+#include <linux/delay.h> static int snd_ctl_open(struct inode *inode, struct file *file) { unsigned long flags; @@ -61,6 +62,10 @@ static int snd_ctl_open(struct inode *inode, struct file *file) err = -ENODEV; goto __error1; }
printk("msleep o %p\n", card);msleep(5000);printk("msleep o+\n");- err = snd_card_file_add(card, file); if (err < 0) { err = -ENODEV;