[Xen-devel] Regression introduced by bfcfaa77bdf0f775263e906015982a608df01c76 (vfs: use 'unsigned long' accesses for dcache name comparison and hashing)

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Hey Linus,

I am not sure how to debug this but with v3.3 with just that git commit I can't
start an user space application called 'xenstored'. A bit of strace showed me:
[edit, also with todays linus/master I get the same issue, and if I revert
your patch it works again]

(right is 3.3, left is with your patch)
write(3, "Checking store complete.\n", 25) = 25                 write(3, 
"Checking store complete.\n", 25) = 25
sendto(9, "<11>Mar 22 18:00:27 xenstored: C"..., 55, MSG_NOSI | sendto(9, 
"<11>Mar 22 18:06:44 xenstored: C"..., 55, MSG_NOSI
open("/proc/xen/privcmd", O_RDWR)       = 10                    
open("/proc/xen/privcmd", O_RDWR)       = 10
fcntl(10, F_GETFD)                      = 0                     fcntl(10, 
F_GETFD)                      = 0
fcntl(10, F_SETFD, FD_CLOEXEC)          = 0                     fcntl(10, 
F_SETFD, FD_CLOEXEC)          = 0
open("/dev/xen/evtchn", O_RDWR)         = 11                    
open("/dev/xen/evtchn", O_RDWR)         = 11
open("/proc/xen/xsd_port", O_RDONLY)    = -1 ENOENT (No such  | 
open("/proc/xen/xsd_port", O_RDONLY)    = 12
write(2, "FATAL: ", 7FATAL: )                  = 7            | read(12, "25", 
20)                      = 2
write(2, "Failed to initialize dom0 state:"..., 59Failed to i | close(12)       
                        = 0
) = 59                                                        | ioctl(11, 
EVIOCGVERSION, 0x7fff4e3ffc70) = 41
close(10)                               = 0                   | write(3, 
"CREATE connection 0xe2e7b0\n", 27) = 27
close(5)                                = 0                   | 
open("/proc/xen/xsd_kva", O_RDWR)       = 12
close(4)                                = 0                   | mmap(NULL, 
4096, PROT_READ|PROT_WRITE, MAP_SHARED, 12, 0) = 0
exit_group(1)                           = ?                   | close(12)       
                        = 0
                                                              > ioctl(11, 
EVIOCGKEYCODE or EVIOCSKEYCODE, 0x7fff4e3ffc90) = 0
                                                              > ioctl(11, 
0x44500, 0x7fff4e3ffc90)      = 42
                                                              > 
rt_sigaction(SIGHUP, {0x402180, [HUP], SA_RESTORER|SA_RESTART
                                                              > select(12, [4 5 
6 11], [], NULL, NULL)  = 1 (in [11])
                                                              > read(11, 
")\0\0\0", 4)                  = 4
                                                              > write(11, 
")\0\0\0", 4)                 = 4
                                                              > select(12, [4 5 
6 11], [], NULL, NULL <unfinished ...>

and if I ls /proc/xen (v3.3):

> ls -al /proc/xen
total 0
drwxr-xr-x   2 root root 0 Mar 22 18:05 .
dr-xr-xr-x 126 root root 0 Mar 22 18:05 ..
-r--r--r--   1 root root 0 Mar 22 18:05 capabilities
-rw-------   1 root root 0 Mar 22 18:05 privcmd
-rw-------   1 root root 0 Mar 22 18:05 xenbus
-rw-------   1 root root 0 Mar 22 18:05 xsd_port

while v3.3 with your patch:


8:01:09 # 10 :/proc/xen/ 
> ls -al
ls: cannot access xsd_port: No such file or directory
total 0
drwxr-xr-x   2 root root 0 Mar 22 17:57 .
dr-xr-xr-x 126 root root 0 Mar 22 17:57 ..
-r--r--r--   1 root root 0 Mar 22 17:57 capabilities
-rw-------   1 root root 0 Mar 22 17:57 privcmd
-rw-------   1 root root 0 Mar 22 17:57 xenbus
-rw-------   1 root root 0 Mar 22 17:57 xsd_kva
-?????????   ? ?    ?    ?            ? xsd_port


Looking at the code that sets up 'xsd_port' it looks pretty innocent
and similar to other drivers (ibmasm for example).

Also attached is the .config

Note: to actually bootup the latest with Xen there are some fixes required
to fix the regressions introduced:
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=commit;h=106b44388d8f76373149c4ea144f717b6d4d9a6d
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=commit;h=a759ceb7d1dfe38f4dda147e233aa53c8f477e2a
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=commit;h=1b34ba936c1adff3020eec1e1834ffa4cf89802f
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=commit;h=6ac72c4bc49a9afb02b8176b48be019dff0560cd

Attachment: config-for-linus
Description: Text document

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