current BK boot failure, d_alloc()

current BK boot failure, d_alloc()

[Jens Axboe]

Hi,

SBF: Simple Boot Flag extension found and enabled.
SBF: Setting boot flags 0x80
Starting balanced_irq
Enabling SEP on CPU 1
Enabling SEP on CPU 0

Program received signal SIGSEGV, Segmentation fault.
0xc016da64 in d_alloc (parent=0x0, name=0xdff8fea8) at
include/asm/string.h:196
196     __asm__ __volatile__(
(gdb) bt
#0  0xc016da64 in d_alloc (parent=0x0, name=0xdff8fea8)
    at include/asm/string.h:196
#1  0xc016dd16 in d_alloc_root (root_inode=0xc176ddc4) at
fs/dcache.c:787
#2  0xc014f46b in shmem_fill_super (sb=0xc176ddc4, data=0x1, silent=0)
    at mm/shmem.c:1738
#3  0xc015cabf in get_sb_nodev (fs_type=0x1, flags=-1049174588,
data=0x1, 
    fill_super=0xc014f330 <shmem_fill_super>) at fs/super.c:586
#4  0xc015cc16 in do_kern_mount (fstype=0x1 <Address 0x1 out of bounds>, 
    flags=1, name=0xc02c3547 "tmpfs", data=0x1) at fs/super.c:639
#5  0xc015ccb7 in kern_mount (type=0x1) at fs/super.c:665
#6  0xc0346620 in init_tmpfs () at mm/shmem.c:1887
#7  0xc0338992 in do_initcalls () at init/main.c:486
#8  0xc01050f5 in init (unused=0x0) at init/main.c:551
(gdb) print *(struct qstr *) name
$1 = {name = 0x0, len = 1, hash = 0, name_str = 0xdff8feb4 "\230µÿß\200µÿß"}

craps out in memcpy() due to name->name == NULL

-- 
Jens Axboe

Re: current BK boot failure, d_alloc()

[Jens Axboe]

On Mon, Mar 24 2003, Jens Axboe wrote:
> Hi,
> 
> SBF: Simple Boot Flag extension found and enabled.
> SBF: Setting boot flags 0x80
> Starting balanced_irq
> Enabling SEP on CPU 1
> Enabling SEP on CPU 0
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0xc016da64 in d_alloc (parent=0x0, name=0xdff8fea8) at
> include/asm/string.h:196
> 196     __asm__ __volatile__(
> (gdb) bt
> #0  0xc016da64 in d_alloc (parent=0x0, name=0xdff8fea8)
>     at include/asm/string.h:196
> #1  0xc016dd16 in d_alloc_root (root_inode=0xc176ddc4) at
> fs/dcache.c:787
> #2  0xc014f46b in shmem_fill_super (sb=0xc176ddc4, data=0x1, silent=0)
>     at mm/shmem.c:1738
> #3  0xc015cabf in get_sb_nodev (fs_type=0x1, flags=-1049174588,
> data=0x1, 
>     fill_super=0xc014f330 <shmem_fill_super>) at fs/super.c:586
> #4  0xc015cc16 in do_kern_mount (fstype=0x1 <Address 0x1 out of bounds>, 
>     flags=1, name=0xc02c3547 "tmpfs", data=0x1) at fs/super.c:639
> #5  0xc015ccb7 in kern_mount (type=0x1) at fs/super.c:665
> #6  0xc0346620 in init_tmpfs () at mm/shmem.c:1887
> #7  0xc0338992 in do_initcalls () at init/main.c:486
> #8  0xc01050f5 in init (unused=0x0) at init/main.c:551
> (gdb) print *(struct qstr *) name
> $1 = {name = 0x0, len = 1, hash = 0, name_str = 0xdff8feb4 "\230µÿß\200µÿß"}
> 
> craps out in memcpy() due to name->name == NULL

smells like a compiler problem, with the following patch:

===== fs/dcache.c 1.43 vs edited =====
--- 1.43/fs/dcache.c	Sat Mar 22 05:05:21 2003
+++ edited/fs/dcache.c	Mon Mar 24 12:58:19 2003
@@ -784,7 +784,8 @@
 	struct dentry *res = NULL;
 
 	if (root_inode) {
-		res = d_alloc(NULL, &(const struct qstr) { "/", 1, 0 });
+		struct qstr name = { .name = "/", .len = 1, .hash = 0 };
+		res = d_alloc(NULL, &name);
 		if (res) {
 			res->d_sb = root_inode->i_sb;
 			res->d_parent = res;

-- 
Jens Axboe

Re: current BK boot failure, d_alloc()

[Randy.Dunlap]

> On Mon, Mar 24 2003, Jens Axboe wrote:
>> Hi,
>>
>>
[snip]
>> craps out in memcpy() due to name->name == NULL
>
> smells like a compiler problem, with the following patch:
>
> ===== fs/dcache.c 1.43 vs edited =====
> --- 1.43/fs/dcache.c	Sat Mar 22 05:05:21 2003
> +++ edited/fs/dcache.c	Mon Mar 24 12:58:19 2003
> @@ -784,7 +784,8 @@
>  	struct dentry *res = NULL;
>
>  	if (root_inode) {
> -		res = d_alloc(NULL, &(const struct qstr) { "/", 1, 0 });
> +		struct qstr name = { .name = "/", .len = 1, .hash = 0 };
> +		res = d_alloc(NULL, &name);
>  		if (res) {
>  			res->d_sb = root_inode->i_sb;
>  			res->d_parent = res;
>
> --

what compiler, please?

~Randy

Re: current BK boot failure, d_alloc()

[Jens Axboe]

On Mon, Mar 24 2003, Randy.Dunlap wrote:
> > On Mon, Mar 24 2003, Jens Axboe wrote:
> >> Hi,
> >>
> >>
> [snip]
> >> craps out in memcpy() due to name->name == NULL
> >
> > smells like a compiler problem, with the following patch:
> >
> > ===== fs/dcache.c 1.43 vs edited =====
> > --- 1.43/fs/dcache.c	Sat Mar 22 05:05:21 2003
> > +++ edited/fs/dcache.c	Mon Mar 24 12:58:19 2003
> > @@ -784,7 +784,8 @@
> >  	struct dentry *res = NULL;
> >
> >  	if (root_inode) {
> > -		res = d_alloc(NULL, &(const struct qstr) { "/", 1, 0 });
> > +		struct qstr name = { .name = "/", .len = 1, .hash = 0 };
> > +		res = d_alloc(NULL, &name);
> >  		if (res) {
> >  			res->d_sb = root_inode->i_sb;
> >  			res->d_parent = res;
> >
> > --
> 
> what compiler, please?

gcc 3.3 pre-release, I cannot reproduce it in userspace though. I'll try
and take a look at the generated code.

-- 
Jens Axboe