Re: fs: panic in mnt_set_mountpoint

2014-08-20 Thread Jonas Jensen 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 4246696dc678..a6815027f225 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -736,6 +736,7 @@ static struct mountpoint *new_mountpoint(struct dentry 
> *dentry)
> return ERR_PTR(ret);
> }
>
> +   INIT_HLIST_HEAD(>m_list);
> mp->m_dentry = dentry;
> mp->m_count = 1;
> hlist_add_head(>m_hash, chain);

I can confirm this has been fixed in next-20140820, my boards boot
without panic after rebase (commit: "Merge remote-tracking branch
'vfs/for-next'" - 002561f4e9e40e5444a8776daeaa4e5a718c376c).

Thanks!


   Jonas
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Re: fs: panic in mnt_set_mountpoint

2014-08-20 Thread Jonas Jensen 
 diff --git a/fs/namespace.c b/fs/namespace.c
 index 4246696dc678..a6815027f225 100644
 --- a/fs/namespace.c
 +++ b/fs/namespace.c
 @@ -736,6 +736,7 @@ static struct mountpoint *new_mountpoint(struct dentry 
 *dentry)
 return ERR_PTR(ret);
 }

 +   INIT_HLIST_HEAD(mp-m_list);
 mp-m_dentry = dentry;
 mp-m_count = 1;
 hlist_add_head(mp-m_hash, chain);

I can confirm this has been fixed in next-20140820, my boards boot
without panic after rebase (commit: Merge remote-tracking branch
'vfs/for-next' - 002561f4e9e40e5444a8776daeaa4e5a718c376c).

Thanks!


   Jonas
--
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Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Kevin Hilman 
On Mon, Aug 18, 2014 at 8:33 AM, Thierry Reding
 wrote:
> On Mon, Aug 18, 2014 at 01:09:24PM +0200, Jonas Jensen wrote:
>> Hi,
>>
>> I've run into a kernel panic [1] in next-20140818 you might find interesting.
>>
>> It surprised me because there was never an error in next-20140815, I
>> did a search for related panics but it came up empty.
>>
>> The board boots fine after applying the following:
>>
>> diff --git a/fs/namespace.c b/fs/namespace.c
>> index 1a2bbef..b408a9d 100644
>> --- a/fs/namespace.c
>> +++ b/fs/namespace.c
>> @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
>>  {
>> if (!--mp->m_count) {
>> struct dentry *dentry = mp->m_dentry;
>> -   BUG_ON(!hlist_empty(>m_list));
>> +/* BUG_ON(!hlist_empty(>m_list));*/
>> spin_lock(>d_lock);
>> dentry->d_flags &= ~DCACHE_MOUNTED;
>> spin_unlock(>d_lock);
>> @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
>> child_mnt->mnt_mountpoint = dget(mp->m_dentry);
>> child_mnt->mnt_parent = mnt;
>> child_mnt->mnt_mp = mp;
>> -   hlist_add_head(_mnt->mnt_mp_list, >m_list);
>> +/* hlist_add_head(_mnt->mnt_mp_list, >m_list);*/
>>  }
>>
>>
>> [1]
>> Uncompressing Linux... done, booting the kernel.
>> [ 0.00] Booting Linux on physical CPU 0x0
>> [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
>> version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
>> 10:58:16 CEST 2014
>> [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
>> [ 0.00] CPU: VIVT data cache, VIVT instruction cache
>> [ 0.00] Machine model: MOXA UC-7112-LX
>> [ 0.00] bootconsole [earlycon0] enabled
>> [ 0.00] Memory policy: Data cache writeback
>> [ 0.00] On node 0 totalpages: 8192
>> [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map 
>> c1fba000
>> [ 0.00] Normal zone: 64 pages used for memmap
>> [ 0.00] Normal zone: 0 pages reserved
>> [ 0.00] Normal zone: 8192 pages, LIFO batch:0
>> [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
>> [ 0.00] pcpu-alloc: [0] 0
>> [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
>> Total pages: 8128
>> [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
>> root=/dev/mmcblk0p1 rw rootwait debug
>> [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
>> [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
>> [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
>> [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
>> rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
>> [ 0.00] Virtual kernel memory layout:
>> [ 0.00] vector : 0x - 0x1000 ( 4 kB)
>> [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
>> [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
>> [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
>> [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
>> [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
>> [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
>> [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
>> [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
>> [ 0.00] Preemptible hierarchical RCU implementation.
>> [ 0.00] NR_IRQS:16 nr_irqs:16 16
>> [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
>> wraps every 2147483648000ns
>> [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
>> [ 0.09] pid_max: default: 4096 minimum: 301
>> [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
>> [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
>> [ 0.11] CPU: Testing write buffer coherency: ok
>> [ 0.12] Setting up static identity map for 0x296938 - 0x296980
>> [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003
>
> I've been seeing the same crash starting with next-20140818. I have slab
> allocation debugging enabled and the above unhandled fault is apparently
> caused by in-use poisoning:
>
> [0.301383] Unable to handle kernel paging request at virtual 
> address 5a5a5a5e
>
> The below patch works "fixes" it for me, though I have no idea why it's
> needed all of a sudden.

FWIW, bisecting the boot failure between next-20140818 (bad) and
v3.17-rc1 (good) points the finger at:
# first bad commit: [89f7ca1af15bdfe7a6aed343032a84af2a69f736] vfs:
Keep a list of mounts on a mount point.

Kevin
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Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Thierry Reding 
On Mon, Aug 18, 2014 at 01:09:24PM +0200, Jonas Jensen wrote:
> Hi,
> 
> I've run into a kernel panic [1] in next-20140818 you might find interesting.
> 
> It surprised me because there was never an error in next-20140815, I
> did a search for related panics but it came up empty.
> 
> The board boots fine after applying the following:
> 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 1a2bbef..b408a9d 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
>  {
> if (!--mp->m_count) {
> struct dentry *dentry = mp->m_dentry;
> -   BUG_ON(!hlist_empty(>m_list));
> +/* BUG_ON(!hlist_empty(>m_list));*/
> spin_lock(>d_lock);
> dentry->d_flags &= ~DCACHE_MOUNTED;
> spin_unlock(>d_lock);
> @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
> child_mnt->mnt_mountpoint = dget(mp->m_dentry);
> child_mnt->mnt_parent = mnt;
> child_mnt->mnt_mp = mp;
> -   hlist_add_head(_mnt->mnt_mp_list, >m_list);
> +/* hlist_add_head(_mnt->mnt_mp_list, >m_list);*/
>  }
> 
> 
> [1]
> Uncompressing Linux... done, booting the kernel.
> [ 0.00] Booting Linux on physical CPU 0x0
> [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
> version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
> 10:58:16 CEST 2014
> [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
> [ 0.00] CPU: VIVT data cache, VIVT instruction cache
> [ 0.00] Machine model: MOXA UC-7112-LX
> [ 0.00] bootconsole [earlycon0] enabled
> [ 0.00] Memory policy: Data cache writeback
> [ 0.00] On node 0 totalpages: 8192
> [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
> [ 0.00] Normal zone: 64 pages used for memmap
> [ 0.00] Normal zone: 0 pages reserved
> [ 0.00] Normal zone: 8192 pages, LIFO batch:0
> [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
> [ 0.00] pcpu-alloc: [0] 0
> [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
> Total pages: 8128
> [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
> root=/dev/mmcblk0p1 rw rootwait debug
> [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
> [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
> [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
> [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
> rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
> [ 0.00] Virtual kernel memory layout:
> [ 0.00] vector : 0x - 0x1000 ( 4 kB)
> [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
> [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
> [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
> [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
> [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
> [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
> [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
> [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
> [ 0.00] Preemptible hierarchical RCU implementation.
> [ 0.00] NR_IRQS:16 nr_irqs:16 16
> [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
> wraps every 2147483648000ns
> [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
> [ 0.09] pid_max: default: 4096 minimum: 301
> [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
> [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
> [ 0.11] CPU: Testing write buffer coherency: ok
> [ 0.12] Setting up static identity map for 0x296938 - 0x296980
> [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003

I've been seeing the same crash starting with next-20140818. I have slab
allocation debugging enabled and the above unhandled fault is apparently
caused by in-use poisoning:

[0.301383] Unable to handle kernel paging request at virtual 
address 5a5a5a5e

The below patch works "fixes" it for me, though I have no idea why it's
needed all of a sudden.

Thierry

diff --git a/fs/namespace.c b/fs/namespace.c
index 4246696dc678..a6815027f225 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -736,6 +736,7 @@ static struct mountpoint *new_mountpoint(struct dentry 
*dentry)
return ERR_PTR(ret);
}
 
+   INIT_HLIST_HEAD(>m_list);
mp->m_dentry = dentry;
mp->m_count = 1;
hlist_add_head(>m_hash, chain);


pgp2dkfSG5Xkh.pgp
Description: PGP signature

Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Ming Lei 
On Mon, Aug 18, 2014 at 7:09 PM, Jonas Jensen  wrote:
> Hi,
>
> I've run into a kernel panic [1] in next-20140818 you might find interesting.
>
> It surprised me because there was never an error in next-20140815, I
> did a search for related panics but it came up empty.
>
> The board boots fine after applying the following:
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 1a2bbef..b408a9d 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
>  {
> if (!--mp->m_count) {
> struct dentry *dentry = mp->m_dentry;
> -   BUG_ON(!hlist_empty(>m_list));
> +/* BUG_ON(!hlist_empty(>m_list));*/
> spin_lock(>d_lock);
> dentry->d_flags &= ~DCACHE_MOUNTED;
> spin_unlock(>d_lock);
> @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
> child_mnt->mnt_mountpoint = dget(mp->m_dentry);
> child_mnt->mnt_parent = mnt;
> child_mnt->mnt_mp = mp;
> -   hlist_add_head(_mnt->mnt_mp_list, >m_list);
> +/* hlist_add_head(_mnt->mnt_mp_list, >m_list);*/
>  }
>
>
> [1]
> Uncompressing Linux... done, booting the kernel.
> [ 0.00] Booting Linux on physical CPU 0x0
> [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
> version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
> 10:58:16 CEST 2014
> [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
> [ 0.00] CPU: VIVT data cache, VIVT instruction cache
> [ 0.00] Machine model: MOXA UC-7112-LX
> [ 0.00] bootconsole [earlycon0] enabled
> [ 0.00] Memory policy: Data cache writeback
> [ 0.00] On node 0 totalpages: 8192
> [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
> [ 0.00] Normal zone: 64 pages used for memmap
> [ 0.00] Normal zone: 0 pages reserved
> [ 0.00] Normal zone: 8192 pages, LIFO batch:0
> [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
> [ 0.00] pcpu-alloc: [0] 0
> [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
> Total pages: 8128
> [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
> root=/dev/mmcblk0p1 rw rootwait debug
> [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
> [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
> [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
> [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
> rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
> [ 0.00] Virtual kernel memory layout:
> [ 0.00] vector : 0x - 0x1000 ( 4 kB)
> [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
> [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
> [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
> [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
> [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
> [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
> [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
> [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
> [ 0.00] Preemptible hierarchical RCU implementation.
> [ 0.00] NR_IRQS:16 nr_irqs:16 16
> [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
> wraps every 2147483648000ns
> [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
> [ 0.09] pid_max: default: 4096 minimum: 301
> [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
> [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
> [ 0.11] CPU: Testing write buffer coherency: ok
> [ 0.12] Setting up static identity map for 0x296938 - 0x296980
> [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003
> [ 0.14] Internal error: : 801 [#1] PREEMPT ARM
> [ 0.14] CPU: 0 PID: 11 Comm: kdevtmpfs Not tainted
> 3.17.0-rc1-next-20140818+ #2691
> [ 0.14] task: c184a360 ti: c185 task.ti: c185
> [ 0.14] PC is at mnt_set_mountpoint+0x8c/0x9c
> [ 0.14] LR is at mnt_set_mountpoint+0x70/0x9c
> [ 0.14] pc : [] lr : [] psr: a053
> [ 0.14] sp : c1851e18 ip : 0001 fp : 
> [ 0.14] r10: c1802ae0 r9 : c1802ba0 r8 : 
> [ 0.14] r7 : c1402000 r6 : c1842240 r5 : c1842300 r4 : c1802ba0
> [ 0.14] r3 :  r2 : c184237c r1 : c1802ba0 r0 : c1402054
> [ 0.14] Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel
> [ 0.14] Control: 397f Table: 4000 DAC: 0017
> [ 0.14] Process kdevtmpfs (pid: 11, stack limit = 0xc18501c0)
> [ 0.14] Stack: (0xc1851e18 to 0xc1852000)
> [ 0.14] 1e00: 000dc1842300
> [ 0.14] 1e20:
> c1842300c1802ba0c1842240c00a9464c1842300c1802ba0c1842300
> [ 0.14] 1e40:
> 0020c1802ba0c1851e70c1802b00c1852000c00a96a4c0354690
> [ 0.14] 1e60:
> 0020c1842310c034db48c00aad54c1842250c1402000c1851ec4
> [

fs: panic in mnt_set_mountpoint

2014-08-18 Thread Jonas Jensen 
Hi,

I've run into a kernel panic [1] in next-20140818 you might find interesting.

It surprised me because there was never an error in next-20140815, I
did a search for related panics but it came up empty.

The board boots fine after applying the following:

diff --git a/fs/namespace.c b/fs/namespace.c
index 1a2bbef..b408a9d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
 {
if (!--mp->m_count) {
struct dentry *dentry = mp->m_dentry;
-   BUG_ON(!hlist_empty(>m_list));
+/* BUG_ON(!hlist_empty(>m_list));*/
spin_lock(>d_lock);
dentry->d_flags &= ~DCACHE_MOUNTED;
spin_unlock(>d_lock);
@@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
child_mnt->mnt_mountpoint = dget(mp->m_dentry);
child_mnt->mnt_parent = mnt;
child_mnt->mnt_mp = mp;
-   hlist_add_head(_mnt->mnt_mp_list, >m_list);
+/* hlist_add_head(_mnt->mnt_mp_list, >m_list);*/
 }


[1]
Uncompressing Linux... done, booting the kernel.
[ 0.00] Booting Linux on physical CPU 0x0
[ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
10:58:16 CEST 2014
[ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
[ 0.00] CPU: VIVT data cache, VIVT instruction cache
[ 0.00] Machine model: MOXA UC-7112-LX
[ 0.00] bootconsole [earlycon0] enabled
[ 0.00] Memory policy: Data cache writeback
[ 0.00] On node 0 totalpages: 8192
[ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
[ 0.00] Normal zone: 64 pages used for memmap
[ 0.00] Normal zone: 0 pages reserved
[ 0.00] Normal zone: 8192 pages, LIFO batch:0
[ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.00] pcpu-alloc: [0] 0
[ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
Total pages: 8128
[ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
root=/dev/mmcblk0p1 rw rootwait debug
[ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
[ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
[ 0.00] Virtual kernel memory layout:
[ 0.00] vector : 0x - 0x1000 ( 4 kB)
[ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
[ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
[ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
[ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
[ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
[ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
[ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
[ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.00] Preemptible hierarchical RCU implementation.
[ 0.00] NR_IRQS:16 nr_irqs:16 16
[ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
wraps every 2147483648000ns
[ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
[ 0.09] pid_max: default: 4096 minimum: 301
[ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.11] CPU: Testing write buffer coherency: ok
[ 0.12] Setting up static identity map for 0x296938 - 0x296980
[ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003
[ 0.14] Internal error: : 801 [#1] PREEMPT ARM
[ 0.14] CPU: 0 PID: 11 Comm: kdevtmpfs Not tainted
3.17.0-rc1-next-20140818+ #2691
[ 0.14] task: c184a360 ti: c185 task.ti: c185
[ 0.14] PC is at mnt_set_mountpoint+0x8c/0x9c
[ 0.14] LR is at mnt_set_mountpoint+0x70/0x9c
[ 0.14] pc : [] lr : [] psr: a053
[ 0.14] sp : c1851e18 ip : 0001 fp : 
[ 0.14] r10: c1802ae0 r9 : c1802ba0 r8 : 
[ 0.14] r7 : c1402000 r6 : c1842240 r5 : c1842300 r4 : c1802ba0
[ 0.14] r3 :  r2 : c184237c r1 : c1802ba0 r0 : c1402054
[ 0.14] Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel
[ 0.14] Control: 397f Table: 4000 DAC: 0017
[ 0.14] Process kdevtmpfs (pid: 11, stack limit = 0xc18501c0)
[ 0.14] Stack: (0xc1851e18 to 0xc1852000)
[ 0.14] 1e00: 000dc1842300
[ 0.14] 1e20:
c1842300c1802ba0c1842240c00a9464c1842300c1802ba0c1842300
[ 0.14] 1e40:
0020c1802ba0c1851e70c1802b00c1852000c00a96a4c0354690
[ 0.14] 1e60:
0020c1842310c034db48c00aad54c1842250c1402000c1851ec4
[ 0.14] 1e80:
c18110008000c02fdfb9
[ 0.14] 1ea0:
c00aafccc1852000c1802aa20200c1802ae0
[ 0.14] 1ec0:
c1802b00c1852000c182bf5cc1851f06c182bf5cc0172950c017299c
[

fs: panic in mnt_set_mountpoint

2014-08-18 Thread Jonas Jensen 
Hi,

I've run into a kernel panic [1] in next-20140818 you might find interesting.

It surprised me because there was never an error in next-20140815, I
did a search for related panics but it came up empty.

The board boots fine after applying the following:

diff --git a/fs/namespace.c b/fs/namespace.c
index 1a2bbef..b408a9d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
 {
if (!--mp-m_count) {
struct dentry *dentry = mp-m_dentry;
-   BUG_ON(!hlist_empty(mp-m_list));
+/* BUG_ON(!hlist_empty(mp-m_list));*/
spin_lock(dentry-d_lock);
dentry-d_flags = ~DCACHE_MOUNTED;
spin_unlock(dentry-d_lock);
@@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
child_mnt-mnt_mountpoint = dget(mp-m_dentry);
child_mnt-mnt_parent = mnt;
child_mnt-mnt_mp = mp;
-   hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);
+/* hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);*/
 }


[1]
Uncompressing Linux... done, booting the kernel.
[ 0.00] Booting Linux on physical CPU 0x0
[ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
10:58:16 CEST 2014
[ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
[ 0.00] CPU: VIVT data cache, VIVT instruction cache
[ 0.00] Machine model: MOXA UC-7112-LX
[ 0.00] bootconsole [earlycon0] enabled
[ 0.00] Memory policy: Data cache writeback
[ 0.00] On node 0 totalpages: 8192
[ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
[ 0.00] Normal zone: 64 pages used for memmap
[ 0.00] Normal zone: 0 pages reserved
[ 0.00] Normal zone: 8192 pages, LIFO batch:0
[ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.00] pcpu-alloc: [0] 0
[ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
Total pages: 8128
[ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
root=/dev/mmcblk0p1 rw rootwait debug
[ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
[ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
[ 0.00] Virtual kernel memory layout:
[ 0.00] vector : 0x - 0x1000 ( 4 kB)
[ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
[ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
[ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
[ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
[ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
[ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
[ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
[ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.00] Preemptible hierarchical RCU implementation.
[ 0.00] NR_IRQS:16 nr_irqs:16 16
[ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
wraps every 2147483648000ns
[ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
[ 0.09] pid_max: default: 4096 minimum: 301
[ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.11] CPU: Testing write buffer coherency: ok
[ 0.12] Setting up static identity map for 0x296938 - 0x296980
[ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003
[ 0.14] Internal error: : 801 [#1] PREEMPT ARM
[ 0.14] CPU: 0 PID: 11 Comm: kdevtmpfs Not tainted
3.17.0-rc1-next-20140818+ #2691
[ 0.14] task: c184a360 ti: c185 task.ti: c185
[ 0.14] PC is at mnt_set_mountpoint+0x8c/0x9c
[ 0.14] LR is at mnt_set_mountpoint+0x70/0x9c
[ 0.14] pc : [c00a8978] lr : [c00a895c] psr: a053
[ 0.14] sp : c1851e18 ip : 0001 fp : 
[ 0.14] r10: c1802ae0 r9 : c1802ba0 r8 : 
[ 0.14] r7 : c1402000 r6 : c1842240 r5 : c1842300 r4 : c1802ba0
[ 0.14] r3 :  r2 : c184237c r1 : c1802ba0 r0 : c1402054
[ 0.14] Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel
[ 0.14] Control: 397f Table: 4000 DAC: 0017
[ 0.14] Process kdevtmpfs (pid: 11, stack limit = 0xc18501c0)
[ 0.14] Stack: (0xc1851e18 to 0xc1852000)
[ 0.14] 1e00: 000dc1842300
[ 0.14] 1e20:
c1842300c1802ba0c1842240c00a9464c1842300c1802ba0c1842300
[ 0.14] 1e40:
0020c1802ba0c1851e70c1802b00c1852000c00a96a4c0354690
[ 0.14] 1e60:
0020c1842310c034db48c00aad54c1842250c1402000c1851ec4
[ 0.14] 1e80:
c18110008000c02fdfb9
[ 0.14] 1ea0:
c00aafccc1852000c1802aa20200c1802ae0
[ 0.14] 1ec0:

Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Ming Lei 
On Mon, Aug 18, 2014 at 7:09 PM, Jonas Jensen jonas.jen...@gmail.com wrote:
 Hi,

 I've run into a kernel panic [1] in next-20140818 you might find interesting.

 It surprised me because there was never an error in next-20140815, I
 did a search for related panics but it came up empty.

 The board boots fine after applying the following:

 diff --git a/fs/namespace.c b/fs/namespace.c
 index 1a2bbef..b408a9d 100644
 --- a/fs/namespace.c
 +++ b/fs/namespace.c
 @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
  {
 if (!--mp-m_count) {
 struct dentry *dentry = mp-m_dentry;
 -   BUG_ON(!hlist_empty(mp-m_list));
 +/* BUG_ON(!hlist_empty(mp-m_list));*/
 spin_lock(dentry-d_lock);
 dentry-d_flags = ~DCACHE_MOUNTED;
 spin_unlock(dentry-d_lock);
 @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
 child_mnt-mnt_mountpoint = dget(mp-m_dentry);
 child_mnt-mnt_parent = mnt;
 child_mnt-mnt_mp = mp;
 -   hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);
 +/* hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);*/
  }


 [1]
 Uncompressing Linux... done, booting the kernel.
 [ 0.00] Booting Linux on physical CPU 0x0
 [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
 version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
 10:58:16 CEST 2014
 [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
 [ 0.00] CPU: VIVT data cache, VIVT instruction cache
 [ 0.00] Machine model: MOXA UC-7112-LX
 [ 0.00] bootconsole [earlycon0] enabled
 [ 0.00] Memory policy: Data cache writeback
 [ 0.00] On node 0 totalpages: 8192
 [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
 [ 0.00] Normal zone: 64 pages used for memmap
 [ 0.00] Normal zone: 0 pages reserved
 [ 0.00] Normal zone: 8192 pages, LIFO batch:0
 [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
 [ 0.00] pcpu-alloc: [0] 0
 [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
 Total pages: 8128
 [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
 root=/dev/mmcblk0p1 rw rootwait debug
 [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
 [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
 [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
 [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
 rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
 [ 0.00] Virtual kernel memory layout:
 [ 0.00] vector : 0x - 0x1000 ( 4 kB)
 [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
 [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
 [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
 [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
 [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
 [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
 [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
 [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
 [ 0.00] Preemptible hierarchical RCU implementation.
 [ 0.00] NR_IRQS:16 nr_irqs:16 16
 [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
 wraps every 2147483648000ns
 [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
 [ 0.09] pid_max: default: 4096 minimum: 301
 [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.11] CPU: Testing write buffer coherency: ok
 [ 0.12] Setting up static identity map for 0x296938 - 0x296980
 [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003
 [ 0.14] Internal error: : 801 [#1] PREEMPT ARM
 [ 0.14] CPU: 0 PID: 11 Comm: kdevtmpfs Not tainted
 3.17.0-rc1-next-20140818+ #2691
 [ 0.14] task: c184a360 ti: c185 task.ti: c185
 [ 0.14] PC is at mnt_set_mountpoint+0x8c/0x9c
 [ 0.14] LR is at mnt_set_mountpoint+0x70/0x9c
 [ 0.14] pc : [c00a8978] lr : [c00a895c] psr: a053
 [ 0.14] sp : c1851e18 ip : 0001 fp : 
 [ 0.14] r10: c1802ae0 r9 : c1802ba0 r8 : 
 [ 0.14] r7 : c1402000 r6 : c1842240 r5 : c1842300 r4 : c1802ba0
 [ 0.14] r3 :  r2 : c184237c r1 : c1802ba0 r0 : c1402054
 [ 0.14] Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel
 [ 0.14] Control: 397f Table: 4000 DAC: 0017
 [ 0.14] Process kdevtmpfs (pid: 11, stack limit = 0xc18501c0)
 [ 0.14] Stack: (0xc1851e18 to 0xc1852000)
 [ 0.14] 1e00: 000dc1842300
 [ 0.14] 1e20:
 c1842300c1802ba0c1842240c00a9464c1842300c1802ba0c1842300
 [ 0.14] 1e40:
 0020c1802ba0c1851e70c1802b00c1852000c00a96a4c0354690
 [ 0.14] 1e60:
 0020c1842310c034db48c00aad54c1842250c1402000c1851ec4
 [ 0.14] 1e80:

Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Thierry Reding 
On Mon, Aug 18, 2014 at 01:09:24PM +0200, Jonas Jensen wrote:
 Hi,
 
 I've run into a kernel panic [1] in next-20140818 you might find interesting.
 
 It surprised me because there was never an error in next-20140815, I
 did a search for related panics but it came up empty.
 
 The board boots fine after applying the following:
 
 diff --git a/fs/namespace.c b/fs/namespace.c
 index 1a2bbef..b408a9d 100644
 --- a/fs/namespace.c
 +++ b/fs/namespace.c
 @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
  {
 if (!--mp-m_count) {
 struct dentry *dentry = mp-m_dentry;
 -   BUG_ON(!hlist_empty(mp-m_list));
 +/* BUG_ON(!hlist_empty(mp-m_list));*/
 spin_lock(dentry-d_lock);
 dentry-d_flags = ~DCACHE_MOUNTED;
 spin_unlock(dentry-d_lock);
 @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
 child_mnt-mnt_mountpoint = dget(mp-m_dentry);
 child_mnt-mnt_parent = mnt;
 child_mnt-mnt_mp = mp;
 -   hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);
 +/* hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);*/
  }
 
 
 [1]
 Uncompressing Linux... done, booting the kernel.
 [ 0.00] Booting Linux on physical CPU 0x0
 [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
 version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
 10:58:16 CEST 2014
 [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
 [ 0.00] CPU: VIVT data cache, VIVT instruction cache
 [ 0.00] Machine model: MOXA UC-7112-LX
 [ 0.00] bootconsole [earlycon0] enabled
 [ 0.00] Memory policy: Data cache writeback
 [ 0.00] On node 0 totalpages: 8192
 [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map c1fba000
 [ 0.00] Normal zone: 64 pages used for memmap
 [ 0.00] Normal zone: 0 pages reserved
 [ 0.00] Normal zone: 8192 pages, LIFO batch:0
 [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
 [ 0.00] pcpu-alloc: [0] 0
 [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
 Total pages: 8128
 [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
 root=/dev/mmcblk0p1 rw rootwait debug
 [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
 [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
 [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
 [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
 rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
 [ 0.00] Virtual kernel memory layout:
 [ 0.00] vector : 0x - 0x1000 ( 4 kB)
 [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
 [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
 [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
 [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
 [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
 [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
 [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
 [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
 [ 0.00] Preemptible hierarchical RCU implementation.
 [ 0.00] NR_IRQS:16 nr_irqs:16 16
 [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
 wraps every 2147483648000ns
 [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
 [ 0.09] pid_max: default: 4096 minimum: 301
 [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.11] CPU: Testing write buffer coherency: ok
 [ 0.12] Setting up static identity map for 0x296938 - 0x296980
 [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003

I've been seeing the same crash starting with next-20140818. I have slab
allocation debugging enabled and the above unhandled fault is apparently
caused by in-use poisoning:

[0.301383] Unable to handle kernel paging request at virtual 
address 5a5a5a5e

The below patch works fixes it for me, though I have no idea why it's
needed all of a sudden.

Thierry

diff --git a/fs/namespace.c b/fs/namespace.c
index 4246696dc678..a6815027f225 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -736,6 +736,7 @@ static struct mountpoint *new_mountpoint(struct dentry 
*dentry)
return ERR_PTR(ret);
}
 
+   INIT_HLIST_HEAD(mp-m_list);
mp-m_dentry = dentry;
mp-m_count = 1;
hlist_add_head(mp-m_hash, chain);


pgp2dkfSG5Xkh.pgp
Description: PGP signature

Re: fs: panic in mnt_set_mountpoint

2014-08-18 Thread Kevin Hilman 
On Mon, Aug 18, 2014 at 8:33 AM, Thierry Reding
thierry.red...@gmail.com wrote:
 On Mon, Aug 18, 2014 at 01:09:24PM +0200, Jonas Jensen wrote:
 Hi,

 I've run into a kernel panic [1] in next-20140818 you might find interesting.

 It surprised me because there was never an error in next-20140815, I
 did a search for related panics but it came up empty.

 The board boots fine after applying the following:

 diff --git a/fs/namespace.c b/fs/namespace.c
 index 1a2bbef..b408a9d 100644
 --- a/fs/namespace.c
 +++ b/fs/namespace.c
 @@ -746,7 +746,7 @@ static void put_mountpoint(struct mountpoint *mp)
  {
 if (!--mp-m_count) {
 struct dentry *dentry = mp-m_dentry;
 -   BUG_ON(!hlist_empty(mp-m_list));
 +/* BUG_ON(!hlist_empty(mp-m_list));*/
 spin_lock(dentry-d_lock);
 dentry-d_flags = ~DCACHE_MOUNTED;
 spin_unlock(dentry-d_lock);
 @@ -810,7 +810,7 @@ void mnt_set_mountpoint(struct mount *mnt,
 child_mnt-mnt_mountpoint = dget(mp-m_dentry);
 child_mnt-mnt_parent = mnt;
 child_mnt-mnt_mp = mp;
 -   hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);
 +/* hlist_add_head(child_mnt-mnt_mp_list, mp-m_list);*/
  }


 [1]
 Uncompressing Linux... done, booting the kernel.
 [ 0.00] Booting Linux on physical CPU 0x0
 [ 0.00] Linux version 3.17.0-rc1-next-20140818+ (i@Ildjarn) (gcc
 version 4.9.0 (crosstool-NG 1.19.0) ) #2691 PREEMPT Mon Aug 18
 10:58:16 CEST 2014
 [ 0.00] CPU: FA526 [66015261] revision 1 (ARMv4), cr=397f
 [ 0.00] CPU: VIVT data cache, VIVT instruction cache
 [ 0.00] Machine model: MOXA UC-7112-LX
 [ 0.00] bootconsole [earlycon0] enabled
 [ 0.00] Memory policy: Data cache writeback
 [ 0.00] On node 0 totalpages: 8192
 [ 0.00] free_area_init_node: node 0, pgdat c035cfb4, node_mem_map 
 c1fba000
 [ 0.00] Normal zone: 64 pages used for memmap
 [ 0.00] Normal zone: 0 pages reserved
 [ 0.00] Normal zone: 8192 pages, LIFO batch:0
 [ 0.00] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
 [ 0.00] pcpu-alloc: [0] 0
 [ 0.00] Built 1 zonelists in Zone order, mobility grouping on.
 Total pages: 8128
 [ 0.00] Kernel command line: console=ttyS0,115200n8 earlyprintk
 root=/dev/mmcblk0p1 rw rootwait debug
 [ 0.00] PID hash table entries: 128 (order: -3, 512 bytes)
 [ 0.00] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
 [ 0.00] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
 [ 0.00] Memory: 28852K/32768K available (2718K kernel code, 93K
 rwdata, 484K rodata, 115K init, 126K bss, 3916K reserved)
 [ 0.00] Virtual kernel memory layout:
 [ 0.00] vector : 0x - 0x1000 ( 4 kB)
 [ 0.00] fixmap : 0xffc0 - 0xffe0 (2048 kB)
 [ 0.00] vmalloc : 0xc280 - 0xff00 ( 968 MB)
 [ 0.00] lowmem : 0xc000 - 0xc200 ( 32 MB)
 [ 0.00] .text : 0xc0008000 - 0xc0328aec (3203 kB)
 [ 0.00] .init : 0xc0329000 - 0xc0345ddc ( 116 kB)
 [ 0.00] .data : 0xc0346000 - 0xc035d700 ( 94 kB)
 [ 0.00] .bss : 0xc035d700 - 0xc037cf24 ( 127 kB)
 [ 0.00] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
 [ 0.00] Preemptible hierarchical RCU implementation.
 [ 0.00] NR_IRQS:16 nr_irqs:16 16
 [ 0.00] sched_clock: 32 bits at 100 Hz, resolution 1000ns,
 wraps every 2147483648000ns
 [ 0.01] Calibrating delay loop... 147.86 BogoMIPS (lpj=739328)
 [ 0.09] pid_max: default: 4096 minimum: 301
 [ 0.09] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.10] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
 [ 0.11] CPU: Testing write buffer coherency: ok
 [ 0.12] Setting up static identity map for 0x296938 - 0x296980
 [ 0.14] Unhandled fault: alignment exception (0x801) at 0x0003

 I've been seeing the same crash starting with next-20140818. I have slab
 allocation debugging enabled and the above unhandled fault is apparently
 caused by in-use poisoning:

 [0.301383] Unable to handle kernel paging request at virtual 
 address 5a5a5a5e

 The below patch works fixes it for me, though I have no idea why it's
 needed all of a sudden.

FWIW, bisecting the boot failure between next-20140818 (bad) and
v3.17-rc1 (good) points the finger at:
# first bad commit: [89f7ca1af15bdfe7a6aed343032a84af2a69f736] vfs:
Keep a list of mounts on a mount point.

Kevin
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