Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Can you please try to mount this filesystem via NFS ?

Hai Titus,

Thanks for your quick response. I tried via NFS, Its working. But sd card not working.

Please find below log.

EXT4-fs (mmcblk0p2): recovery complete
EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) on device 179:2.
devtmpfs: mounted
Freeing unused kernel memory: 176K (c056e000 - c059a000)
This architecture does not have kernel memory protection.
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

CPU: 0 PID: 1 Comm: init Not tainted 4.4.12_IPNC_DM365EVM_5.1.0 #10
Hardware name: DaVinci DM365 EVM
Backtrace:
[<c000d1f0>] (dump_backtrace) from [<c000d3ec>] (show_stack+0x18/0x1c)
r7:c3033e58 r6:c3034000 r5:c05a6a90 r4:c05cc228
[<c000d3d4>] (show_stack) from [<c0206af4>] (dump_stack+0x20/0x28)
[<c0206ad4>] (dump_stack) from [<c006f180>] (panic+0x8c/0x1f0)
[<c006f0f8>] (panic) from [<c0019114>] (do_exit+0x478/0x888)
r3:c303c000 r2:00000000 r1:0000000b r0:c04f7acd
r7:c3033e58
[<c0018c9c>] (do_exit) from [<c001a658>] (do_group_exit+0x54/0xf8)
r7:00106001
[<c001a604>] (do_group_exit) from [<c00247a8>] (get_signal+0x56c/0x600)
r7:00106001 r6:c3033ed0 r5:0000000b r4:c3032000
[<c002423c>] (get_signal) from [<c000c9a4>] (do_signal+0x94/0x3ac)
r10:001f9f64 r9:c3032000 r8:00000000 r7:00000000 r6:c3033fb0 r5:00000000
r4:00000000
[<c000c910>] (do_signal) from [<c000ce38>] (do_work_pending+0x60/0xd8)
r9:c3032000 r8:00000000 r7:00000000 r6:00000000 r5:c3033fb0 r4:ffffe000
[<c000cdd8>] (do_work_pending) from [<c000a310>] (slow_work_pending+0xc/0x20)
r7:0005317f r6:ffffffff r5:80000010 r4:000fc750
---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Regards
Bhargav

Can you please share your complete bootup log ?

Hi Titus,

Please find below boot log.

TI UBL Version: 1.50
Booting Catalog Boot Loader
BootMode = SD/MMC
Starting SDMMC Copy...
DONE
Jumping to entry point at 0x81080000.

U-Boot 2016.05 (Sep 07 2016 - 11:00:24 +0530)

Cores: ARM 297 MHz
DDR: 243 MHz
I2C: ready
DRAM: 128 MiB
WARNING: Caches not enabled
NAND: 2048 MiB
MMC: davinci: 0, davinci: 1
Net: DaVinci-EMAC
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Booting from mmc ...
## Error: illegal character '='in variable name "console=ttyS0,115200n8"
reading boot.scr
459 bytes read in 3 ms (149.4 KiB/s)
## Executing script at 80600000
mmc - MMC sub system

Usage:
mmc info - display info of the current MMC device
mmc read addr blk# cnt
mmc write addr blk# cnt
mmc erase blk# cnt
mmc rescan
mmc part - lists available partition on current mmc device
mmc dev [dev] [part] - show or set current mmc device [partition]
mmc list - lists available devices
mmc hwpartition [args...] - does hardware partitioning
arguments (sizes in 512-byte blocks):
[user [enh start cnt] [wrrel {on|off}]] - sets user data area attributes
[gp1|gp2|gp3|gp4 cnt [enh] [wrrel {on|off}]] - general purpose partition
[check|set|complete] - mode, complete set partitioning completed
WARNING: Partitioning is a write-once setting once it is set to complete.
Power cycling is required to initialize partitions after set to complete.
mmc setdsr <value> - set DSR register value

reading uImage

2891592 bytes read in 1263 ms (2.2 MiB/s)
## Booting kernel from Legacy Image at 80700000 ...
Image Name: Linux-4.4.12_IPNC_DM365EVM_5.1.0
Created: 2016-09-12 5:48:25 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2891528 Bytes = 2.8 MiB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Linux version 4.4.12_IPNC_DM365EVM_5.1.0 (bhargav.a@CPU-235U) (gcc version 5.4.1 20160606 (Linaro GCC 5.4-2016.07~dev) ) #10 PREEMPT Mon Sep
12 11:18:21 IST 2016
CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=0005317f
CPU: VIVT data cache, VIVT instruction cache
Machine: DaVinci DM365 EVM
Memory policy: Data cache writeback
DaVinci dm365_rev1.2 variant 0x8
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 13716
Kernel command line: console=ttyS0,115200n8 root=/dev/mmcblk0p2 init=/init rootfstype=ext4 rw ip=off mem=54M video=davincifb:vid0=OFF:vid1=OF
F:osd0=720x576x16,4050K dm365_imp.oper_mode=0 davinci_capture.device_type=4 vpfe_capture.cont_bufsize=6291456 davinci_enc_mngr.ch0_output=COM
PONENT davinci_enc_mngr.ch0_mode=480P-60 rootwait
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 48672K/55296K available (4182K kernel code, 199K rwdata, 1344K rodata, 176K init, 144K bss, 6624K reserved, 0K cma-reserved)
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
vmalloc : 0xc3800000 - 0xff800000 ( 960 MB)
lowmem : 0xc0000000 - 0xc3600000 ( 54 MB)
modules : 0xbf000000 - 0xc0000000 ( 16 MB)
.text : 0xc0008000 - 0xc056df44 (5528 kB)
.init : 0xc056e000 - 0xc059a000 ( 176 kB)
.data : 0xc059a000 - 0xc05cbf40 ( 200 kB)
.bss : 0xc05cbf40 - 0xc05f02e0 ( 145 kB)
SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Preemptible hierarchical RCU implementation.
Build-time adjustment of leaf fanout to 32.
NR_IRQS:245
clocksource: timer0_1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
Console: colour dummy device 80x30
Calibrating delay loop... 146.84 BogoMIPS (lpj=734208)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
CPU: Testing write buffer coherency: ok
Setting up static identity map for 0x80008400 - 0x80008458
devtmpfs: initialized
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
EVM: tvp5146 SD video input
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource timer0_1
NET: Registered protocol family 2
TCP established hash table entries: 1024 (order: 0, 4096 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
futex hash table entries: 256 (order: -1, 3072 bytes)
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
jffs2: version 2.2. (NAND) �© 2001-2006 Red Hat, Inc.
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253)
io scheduler noop registered (default)
Serial: 8250/16550 driver, 2 ports, IRQ sharing disabled
console [ttyS0] disabled
serial8250.0: ttyS0 at MMIO 0x1c20000 (irq = 40, base_baud = 1500000) is a 16550A
console [ttyS0] enabled
serial8250.1: ttyS1 at MMIO 0x1d06000 (irq = 41, base_baud = 7593750) is a 16550A
brd: module loaded
at24 1-0050: 32768 byte 24c256 EEPROM, writable, 64 bytes/write
Read MAC addr from EEPROM: 00:0e:99:03:51:27
nand: No NAND device found
davinci_mdio davinci_mdio.0: davinci mdio revision 1.4
davinci_mdio davinci_mdio.0: detected phy mask fffffffc
libphy: davinci_mdio.0: probed
davinci_mdio davinci_mdio.0: phy[0]: device davinci_mdio-0:00, driver unknown
davinci_mdio davinci_mdio.0: phy[1]: device davinci_mdio-0:01, driver unknown
mousedev: PS/2 mouse device common for all mice
i2c /dev entries driver
davinci-wdt davinci-wdt: heartbeat 60 sec
davinci_mmc da830-mmc.0: Can't get dma_tx channel
davinci_mmc da830-mmc.0: Using PIO, 4-bit mode
davinci_mmc da830-mmc.1: Can't get dma_tx channel
davinci_mmc da830-mmc.1: Using PIO, 4-bit mode
usbcore: registered new interface driver usbhid
mmc0: new SD card at address e624
mmcblk0: mmc0:e624 SD02G 1.84 GiB
usbhid: USB HID core driver
mmcblk0: p1 p2
NET: Registered protocol family 17
console [netcon0] enabled
netconsole: network logging started
ALSA device list:
No soundcards found.
EXT4-fs (mmcblk0p2): recovery complete
EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) on device 179:2.
devtmpfs: mounted
Freeing unused kernel memory: 176K (c056e000 - c059a000)
This architecture does not have kernel memory protection.
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

CPU: 0 PID: 1 Comm: init Not tainted 4.4.12_IPNC_DM365EVM_5.1.0 #10
Hardware name: DaVinci DM365 EVM
Backtrace:
[<c000d1f0>] (dump_backtrace) from [<c000d3ec>] (show_stack+0x18/0x1c)
r7:c3033e58 r6:c3034000 r5:c05a6a90 r4:c05cc228
[<c000d3d4>] (show_stack) from [<c0206af4>] (dump_stack+0x20/0x28)
[<c0206ad4>] (dump_stack) from [<c006f180>] (panic+0x8c/0x1f0)
[<c006f0f8>] (panic) from [<c0019114>] (do_exit+0x478/0x888)
r3:c303c000 r2:00000000 r1:0000000b r0:c04f7acd
r7:c3033e58
[<c0018c9c>] (do_exit) from [<c001a658>] (do_group_exit+0x54/0xf8)
r7:00106001
[<c001a604>] (do_group_exit) from [<c00247a8>] (get_signal+0x56c/0x600)
r7:00106001 r6:c3033ed0 r5:0000000b r4:c3032000
[<c002423c>] (get_signal) from [<c000c9a4>] (do_signal+0x94/0x3ac)
r10:001f9f64 r9:c3032000 r8:00000000 r7:00000000 r6:c3033fb0 r5:00000000
r4:00000000
[<c000c910>] (do_signal) from [<c000ce38>] (do_work_pending+0x60/0xd8)
r9:c3032000 r8:00000000 r7:00000000 r6:00000000 r5:c3033fb0 r4:ffffe000
[<c000cdd8>] (do_work_pending) from [<c000a310>] (slow_work_pending+0xc/0x20)
r7:0005317f r6:ffffffff r5:20000010 r4:ffffa480
---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b


Regards,
Bhargav

Hi Titus,
1) I enabled ext4 support in linux kernel.

CONFIG_EXT2_FS=y
# CONFIG_EXT2_FS_XATTR is not set
CONFIG_EXT3_FS=y
# CONFIG_EXT3_FS_POSIX_ACL is not set
# CONFIG_EXT3_FS_SECURITY is not set
CONFIG_EXT4_FS=y
# CONFIG_EXT4_FS_POSIX_ACL is not set
# CONFIG_EXT4_FS_SECURITY is not set
# CONFIG_EXT4_ENCRYPTION is not set
# CONFIG_EXT4_DEBUG is not set

2) Tried removing init=/init.
3) rootwait added in bootargs.

But, Still facing same issue.

Thanks & Regards,
Bhargav

Can you please provide the complete boot log when you tried to boot NFS ?

Hi Titus,
Thanks for your reply, please find below log (Booted via NFS)

U-Boot 2016.05 (Sep 07 2016 - 11:00:24 +0530)

Cores: ARM 297 MHz
DDR: 243 MHz
I2C: ready
DRAM: 128 MiB
WARNING: Caches not enabled
NAND: 2048 MiB
MMC: davinci: 0, davinci: 1
Net: DaVinci-EMAC
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Booting from mmc ...
## Error: illegal character '='in variable name "console=ttyS0,115200n8"
reading boot.scr
548 bytes read in 7 ms (76.2 KiB/s)
## Executing script at 80600000
mmc - MMC sub system

Usage:
mmc info - display info of the current MMC device
mmc read addr blk# cnt
mmc write addr blk# cnt
mmc erase blk# cnt
mmc rescan
mmc part - lists available partition on current mmc device
mmc dev [dev] [part] - show or set current mmc device [partition]
mmc list - lists available devices
mmc hwpartition [args...] - does hardware partitioning
arguments (sizes in 512-byte blocks):
[user [enh start cnt] [wrrel {on|off}]] - sets user data area attributes
[gp1|gp2|gp3|gp4 cnt [enh] [wrrel {on|off}]] - general purpose partition
[check|set|complete] - mode, complete set partitioning completed
WARNING: Partitioning is a write-once setting once it is set to complete.
Power cycling is required to initialize partitions after set to complete.
mmc setdsr <value> - set DSR register value

reading uImage
2891592 bytes read in 1285 ms (2.1 MiB/s)
## Booting kernel from Legacy Image at 80700000 ...
Image Name: Linux-4.4.12_IPNC_DM365EVM_5.1.0
Created: 2016-09-12 5:48:25 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2891528 Bytes = 2.8 MiB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Linux version 4.4.12_IPNC_DM365EVM_5.1.0 (bhargav.a@CPU-235U) (gcc version 5.4.1 20160606 (Linaro GCC 5.4-2016.07~dev) ) #10 PREEMPT Mon Sep
12 11:18:21 IST 2016
CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=0005317f
CPU: VIVT data cache, VIVT instruction cache
Machine: DaVinci DM365 EVM
Memory policy: Data cache writeback
DaVinci dm365_rev1.2 variant 0x8
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 13716
Kernel command line: console=ttyS0,115200n8 root=/dev/nfs nfsroot=192.168.1.154:/home/bhargav.a/PORT/TIIN_USA_16_012/IPNC_RDK_DM36x_V5.1.0/B
inaries/dm365/filesys/filesys init=/init ip=dhcp mem=54M video=davincifb:vid0=OFF:vid1=OFF:osd0=720x576x16,4050K dm365_imp.oper_mode=0 davinc
i_capture.device_type=4 vpfe_capture.cont_bufsize=6291456 davinci_enc_mngr.ch0_output=COMPONENT davinci_enc_mngr.ch0_mode=480P-60 rootwait
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 48672K/55296K available (4182K kernel code, 199K rwdata, 1344K rodata, 176K init, 144K bss, 6624K reserved, 0K cma-reserved)
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
vmalloc : 0xc3800000 - 0xff800000 ( 960 MB)
lowmem : 0xc0000000 - 0xc3600000 ( 54 MB)
modules : 0xbf000000 - 0xc0000000 ( 16 MB)
.text : 0xc0008000 - 0xc056df44 (5528 kB)
.init : 0xc056e000 - 0xc059a000 ( 176 kB)
.data : 0xc059a000 - 0xc05cbf40 ( 200 kB)
.bss : 0xc05cbf40 - 0xc05f02e0 ( 145 kB)
SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Preemptible hierarchical RCU implementation.
Build-time adjustment of leaf fanout to 32.
NR_IRQS:245
clocksource: timer0_1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
Console: colour dummy device 80x30
Calibrating delay loop... 146.84 BogoMIPS (lpj=734208)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
CPU: Testing write buffer coherency: ok
Setting up static identity map for 0x80008400 - 0x80008458
devtmpfs: initialized
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
EVM: tvp5146 SD video input
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource timer0_1
NET: Registered protocol family 2
TCP established hash table entries: 1024 (order: 0, 4096 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
futex hash table entries: 256 (order: -1, 3072 bytes)
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
jffs2: version 2.2. (NAND) �© 2001-2006 Red Hat, Inc.
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253)
io scheduler noop registered (default)
Serial: 8250/16550 driver, 2 ports, IRQ sharing disabled
console [ttyS0] disabled
serial8250.0: ttyS0 at MMIO 0x1c20000 (irq = 40, base_baud = 1500000) is a 16550A
console [ttyS0] enabled
serial8250.1: ttyS1 at MMIO 0x1d06000 (irq = 41, base_baud = 7593750) is a 16550A
brd: module loaded
at24 1-0050: 32768 byte 24c256 EEPROM, writable, 64 bytes/write
Read MAC addr from EEPROM: 00:0e:99:03:51:27
nand: No NAND device found
davinci_mdio davinci_mdio.0: davinci mdio revision 1.4
davinci_mdio davinci_mdio.0: detected phy mask fffffffc
libphy: davinci_mdio.0: probed
davinci_mdio davinci_mdio.0: phy[0]: device davinci_mdio-0:00, driver unknown
davinci_mdio davinci_mdio.0: phy[1]: device davinci_mdio-0:01, driver unknown
mousedev: PS/2 mouse device common for all mice
i2c /dev entries driver
davinci-wdt davinci-wdt: heartbeat 60 sec
davinci_mmc da830-mmc.0: Can't get dma_tx channel
davinci_mmc da830-mmc.0: Using PIO, 4-bit mode
davinci_mmc da830-mmc.1: Can't get dma_tx channel
davinci_mmc da830-mmc.1: Using PIO, 4-bit mode
usbcore: registered new interface driver usbhid
mmc0: new SD card at address e624
mmcblk0: mmc0:e624 SD02G 1.84 GiB
usbhid: USB HID core driver
mmcblk0: p1 p2
NET: Registered protocol family 17
console [netcon0] enabled
netconsole: network logging started
net eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=davinci_mdio-0:01, id=221613)
davinci_emac davinci_emac.1 eth0: Link is Up - 100Mbps/Full - flow control rx/tx
Sending DHCP requests ..., OK
IP-Config: Got DHCP answer from 192.168.1.1, my address is 192.168.1.132
IP-Config: Complete:
device=eth0, hwaddr=00:0e:99:03:51:27, ipaddr=192.168.1.132, mask=255.255.255.0, gw=192.168.1.1
host=192.168.1.132, domain=pathpartner.com, nis-domain=(none)
bootserver=0.0.0.0, rootserver=192.168.1.154, rootpath=
nameserver0=192.168.7.10, nameserver1=203.201.60.12, nameserver2=202.56.230.2
ALSA device list:
No soundcards found.
VFS: Mounted root (nfs filesystem) on device 0:14.
devtmpfs: mounted
Freeing unused kernel memory: 176K (c056e000 - c059a000)
This architecture does not have kernel memory protection.
/bin/sh: can't access tty; job control turned off
/ #
/ #
/ #
/ #
/ #
/ #

Thanks & Regards,

Bhargav

After NFS boot, able to mount the SD card's 2nd partition and able to see the contents of filesystem?

Hi Titus,

    Yes, I am able to mount sd card after NFS boot, And i can see the contents of SD card's 2nd partition.(able to execute script also).

          I tried prebuilt filesystem and flashed with ext3. Getting shell for the first time with following errors. second time mounting is failed.(sd card corrupted after this). 

Thanks & Regards

Bhargav

Hi Titus,

I tried prebuilt filesystem and flashed with ext3. Getting shell for the first time with following errors. second time mounting is failed.(sd card corrupted after this).

EXT4-fs error (device mmcblk0p2): ext4_lookup:1584: inode #40562: comm swapper: deleted inode referenced: 40633
Starting init: /sbin/init exists but couldn't execute it (error -117)
/bin/sh: can't access tty; job control turned off
EXT4-fs error (device mmcblk0p2): ext4_iget:4173: inode #40689: comm sh: bad extra_isize (57200 != 256)
EXT4-fs error (device mmcblk0p2): ext4_iget:4173: inode #40689: comm sh: bad extra_isize (57200 != 256)
random: nonblocking pool is initialized
/ #
/ #

Thanks & Regards
Bhargav