Re: sysfs_dir_cache growing out of control

Joel Fuster
2007-08-23T03:56:58Z

Joel Fuster wrote:
> Hi,
>
> I am running 2.6.22.3. For reasons that escape me, over time (days) the
> sysfs_dir_cache, dentry, and inode_cache SLUB entries grow until they
> consume all the memory on my system, requiring a reboot.
>
> Although I did not record objective evidence of this at the time, I
> suspect I had the same problem with 2.6.18 and 2.6.20...I certainly had
> the same symptoms.

An update to this...it seems to be related to "scanbuttond" which is an
app that uses libusb to poll a scanner for button presses on the scanner
itself. The number of objects in sysfs_dir_cache stops growing when I
kill the scanbuttond process.

An strace of one poll loop for scanbuttond follows:

nanosleep({0, 333000000}, NULL) = 0
open("/dev/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=80, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 4 entries */, 4096) = 96
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 3 entries */, 4096) = 72
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\0\2\t\0\1@\0\0\0\0\6\2\3\2\1\1", 18) = 18
read(2, "\t\2\31\0\1\1\0\340", 8) = 8
read(2, "\0\t\4\0\0\1\t\0\0\0\7\5\201\3\4\0\f", 17) = 17
close(2) = 0
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=100, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 4 entries */, 4096) = 96
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 3 entries */, 4096) = 72
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\0\2\t\0\1@\0\0\0\0\6\2\3\2\1\1", 18) = 18
read(2, "\t\2\31\0\1\1\0\340", 8) = 8
read(2, "\0\t\4\0\0\1\t\0\0\0\7\5\201\3\4\0\f", 17) = 17
close(2) = 0
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=100, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 5 entries */, 4096) = 120
open("/dev/bus/usb/001/004", O_RDWR) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = 0
read(2, "\22\1\20\1\0\0\0@\330\5\3@\0\1\0\0\0\1", 18) = 18
read(2, "\t\2 \0\1\1\0\240", 8) = 8
read(2, "\372\t\4\0\0\2\377\377\377\0\7\5\201\2@\0\0\7\5\2\2@\0"..., 24)
= 24
close(2) = 0
open("/dev/bus/usb/001/003", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/003", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\20\1\0\0\0@{\6\3#\0\3\1\2\0\1", 18) = 18
read(2, "\t\2\'\0\1\1\0\200", 8) = 8
read(2, "2\t\4\0\0\3\377\0\0\0\7\5\201\3\n\0\1\7\5\2\2@\0\0\7\5"..., 31)
= 31
close(2) = 0
open("/dev/bus/usb/001/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/001", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\20\1\t\0\0@\0\0\0\0\6\2\3\2\1\1", 18) = 18
read(2, "\t\2\31\0\1\1\0\340", 8) = 8
read(2, "\0\t\4\0\0\1\t\0\0\0\7\5\201\3\2\0\377", 17) = 17
close(2) = 0
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/001/004", O_RDWR) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 ENOTTY (Inappropriate
ioctl for device)
close(1) = 0
open("/dev/bus/usb/001/003", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/003", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/001", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=80, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 4 entries */, 4096) = 96
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=60, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 3 entries */, 4096) = 72
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\0\2\t\0\1@\0\0\0\0\6\2\3\2\1\1", 18) = 18
read(2, "\t\2\31\0\1\1\0\340", 8) = 8
read(2, "\0\t\4\0\0\1\t\0\0\0\7\5\201\3\4\0\f", 17) = 17
close(2) = 0
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/002/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 1
fstat(1, {st_mode=S_IFDIR|0755, st_size=100, ...}) = 0
fcntl(1, F_SETFD, FD_CLOEXEC) = 0
getdents(1, /* 5 entries */, 4096) = 120
open("/dev/bus/usb/001/004", O_RDWR) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = 0
read(2, "\22\1\20\1\0\0\0@\330\5\3@\0\1\0\0\0\1", 18) = 18
read(2, "\t\2 \0\1\1\0\240", 8) = 8
read(2, "\372\t\4\0\0\2\377\377\377\0\7\5\201\2@\0\0\7\5\2\2@\0"..., 24)
= 24
close(2) = 0
open("/dev/bus/usb/001/003", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/003", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\20\1\0\0\0@{\6\3#\0\3\1\2\0\1", 18) = 18
read(2, "\t\2\'\0\1\1\0\200", 8) = 8
read(2, "2\t\4\0\0\3\377\0\0\0\7\5\201\3\n\0\1\7\5\2\2@\0\0\7\5"..., 31)
= 31
close(2) = 0
open("/dev/bus/usb/001/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/001", O_RDONLY) = 2
ioctl(2, USBDEVFS_CONNECTINFO, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
read(2, "\22\1\20\1\t\0\0@\0\0\0\0\6\2\3\2\1\1", 18) = 18
read(2, "\t\2\31\0\1\1\0\340", 8) = 8
read(2, "\0\t\4\0\0\1\t\0\0\0\7\5\201\3\2\0\377", 17) = 17
close(2) = 0
getdents(1, /* 0 entries */, 4096) = 0
close(1) = 0
open("/dev/bus/usb/001/004", O_RDWR) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 ENOTTY (Inappropriate
ioctl for device)
close(1) = 0
open("/dev/bus/usb/001/003", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/003", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001/001", O_RDWR) = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/001", O_RDONLY) = 1
ioctl(1, USBDEVFS_IOCTL, 0x7fffb3a08420) = -1 EPERM (Operation not
permitted)
close(1) = 0
open("/dev/bus/usb/001/004", O_RDWR) = 1
ioctl(1, USBDEVFS_CLAIMINTERFACE, 0x7fffb3a0848c) = 0
ioctl(1, USBDEVFS_CONTROL, 0x7fffb3a08420) = 64
ioctl(1, USBDEVFS_CONTROL, 0x7fffb3a08420) = 8
ioctl(1, USBDEVFS_RELEASEINTERFACE, 0x7fffb3a08494) = 0
close(1) = 0
nanosleep({0, 333000000}, <unfinished ...>