- 06 Mar, 2008 2 commits
-
-
Adrian Bunk authored
This patch fixes the following build error with landisk_defconfig when using gcc 4.3: <-- snip --> ... MODPOST 50 modules ERROR: "__udivsi3_i4i" [net/sunrpc/sunrpc.ko] undefined! ERROR: "__udivsi3_i4i" [net/appletalk/appletalk.ko] undefined! ERROR: "__udivsi3_i4i" [fs/ufs/ufs.ko] undefined! ERROR: "__udivsi3_i4i" [fs/ntfs/ntfs.ko] undefined! ERROR: "__sdivsi3_i4i" [fs/ntfs/ntfs.ko] undefined! ERROR: "__udivsi3_i4i" [fs/nfsd/nfsd.ko] undefined! ERROR: "__sdivsi3_i4i" [fs/nfsd/nfsd.ko] undefined! ERROR: "__udivsi3_i4i" [fs/nfs/nfs.ko] undefined! ERROR: "__udivsi3_i4i" [fs/lockd/lockd.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/usb/storage/usb-storage.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/usb/serial/pl2303.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/usb/serial/pl2303.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/usb/serial/ftdi_sio.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/usb/misc/sisusbvga/sisusbvga.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/usb/misc/sisusbvga/sisusbvga.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/media/video/v4l1-compat.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/v4l1-compat.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/usbvideo/vicam.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/media/video/usbvideo/usbvideo.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/usbvideo/usbvideo.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/media/video/sn9c102/sn9c102.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/sn9c102/sn9c102.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/se401.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/media/video/pwc/pwc.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/md/raid0.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/md/md-mod.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/md/md-mod.ko] undefined! ERROR: "__udivsi3_i4i" [drivers/md/linear.ko] undefined! ERROR: "__sdivsi3_i4i" [drivers/hid/usbhid/usbhid.ko] undefined! make[2]: *** [__modpost] Error 1 <-- snip --> Signed-off-by:
Adrian Bunk <adrian.bunk@movial.fi> Signed-off-by:
Paul Mundt <lethal@linux-sh.org>
-
Adrian Bunk authored
This patch fixes the following compile error: <-- snip --> ... CC arch/sh/mm/pg-sh7705.o /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/mm/pg-sh7705.c: In function 'ptep_get_and_clear': /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/mm/pg-sh7705.c:130: error: implicit declaration of function 'mapping_writably_mapped' make[2]: *** [arch/sh/mm/pg-sh7705.o] Error 1 <-- snip --> Signed-off-by:
-
- 05 Mar, 2008 38 commits
-
-
Linus Torvalds authored
-
Pavel Roskin authored
A change after 2.6.24 broke ndiswrapper by accidentally removing its access to GPL-only symbols. Revert that change and add comments about the reasons why ndiswrapper and driverloader are treated in a special way. Signed-off-by:
Pavel Roskin <proski@gnu.org> Acked-by:
Greg KH <gregkh@suse.de> Acked-by:
Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jon Masters <jonathan@jonmasters.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (22 commits) [IPCONFIG]: The kernel gets no IP from some DHCP servers b43legacy: Fix module init message rndis_wlan: fix broken data copy libertas: compare the current command with response libertas: fix sanity check on sequence number in command response p54: fix eeprom parser length sanity checks p54: fix EEPROM structure endianness ssb: Add pcibios_enable_device() return value check rc80211-pid: fix rate adjustment [ESP]: Add select on AUTHENC [TCP]: Improve ipv4 established hash function. [NETPOLL]: Revert two bogus cleanups that broke netconsole. [PPPOL2TP]: Add missing sock_put() in pppol2tp_tunnel_closeall() Subject: [PPPOL2TP] add missing sock_put() in pppol2tp_recv_dequeue() [BLUETOOTH]: l2cap info_timer delete fix in hci_conn_del [NET]: Fix race in generic address resolution. iucv: fix build error on !SMP [TCP]: Must count fack_count also when skipping [TUN]: Fix RTNL-locking in tun/tap driver [SCTP]: Use proc_create to setup de->proc_fops. ...
-
git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6: [SPARC]: Fix link errors with gcc-4.3 sparc64: replace remaining __FUNCTION__ occurances sparc: replace remaining __FUNCTION__ occurances [SPARC]: Add reboot_command[] extern decl to asm/system.h [SPARC]: Mark linux_sparc_{fpu,chips} static.
-
Stephen Hemminger authored
From: Stephen Hemminger <shemminger@linux-foundation.org> Based upon a patch by Marcel Wappler: This patch fixes a DHCP issue of the kernel: some DHCP servers (i.e. in the Linksys WRT54Gv5) are very strict about the contents of the DHCPDISCOVER packet they receive from clients. Table 5 in RFC2131 page 36 requests the fields 'ciaddr' and 'siaddr' MUST be set to '0'. These DHCP servers ignore Linux kernel's DHCP discovery packets with these two fields set to '255.255.255.255' (in contrast to popular DHCP clients, such as 'dhclient' or 'udhcpc'). This leads to a not booting system. Signed-off-by:David S. Miller <davem@davemloft.net>
-
David S. Miller authored
-
git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6Linus Torvalds authored
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] fix ia64 kprobes compilation [IA64] move gcc_intrin.h from header-y to unifdef-y [IA64] workaround tiger ia64_sal_get_physical_id_info hang [IA64] move defconfig to arch/ia64/configs/ [IA64] Fix irq migration in multiple vector domain [IA64] signal(ia64_ia32): add a signal stack overflow check [IA64] signal(ia64): add a signal stack overflow check [IA64] CONFIG_SGI_SN2 - auto select NUMA and ACPI_NUMA
-
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-2.6: debugfs: fix sparse warnings Driver core: Fix cleanup when failing device_add(). driver core: Remove dpm_sysfs_remove() from error path of device_add() PM: fix new mutex-locking bug in the PM core PM: Do not acquire device semaphores upfront during suspend kobject: properly initialize ksets sysfs: CONFIG_SYSFS_DEPRECATED fix driver core: fix up Kconfig text for CONFIG_SYSFS_DEPRECATED
-
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/pci-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/pci-2.6: pci: hotplug: pciehp: fix error code path in hpc_power_off_slot PCI: Add DECLARE_PCI_DEVICE_TABLE macro PCI: fix up error messages for pci_bus registering PCI: fix section mismatch warning in pci_scan_child_bus PCI: consolidate duplicated MSI enable functions PCI: use dev_printk in quirk messages
-
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: USB: ftdi_sio - really enable EM1010PC USB: remove incorrect struct class_device from the printer gadget USB: pxa2xx_udc: fix misuse of clock enable/disable calls USB: ftdi_sio: Workaround for broken Matrix Orbital serial port USB: Add support for AXESSTEL MV110H CDMA modem usb-storage: update earlier scatter-gather bug fix USB: isp116x: fix enumeration on boot USB: ehci: handle large bulk URBs correctly (again) USB: spruce up the device blacklist USB: fix comment of struct usb_interface USB: update Kconfig entry for USB_SUSPEND usb: Add support for the mos7820/7840-based B&B USB/RS485 converter to mos7840.c
-
Masami Hiramatsu authored
Fix a bug in regiseter_kretprobe() which does not check rp->kp.symbol_name == NULL before calling kprobe_lookup_name. For maintainability, this introduces kprobe_addr helper function which resolves addr field. It is used by register_kprobe and register_kretprobe. Signed-off-by:
Masami Hiramatsu <mhiramat@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
-
Randy Dunlap authored
Add to help text that the Intel I2C ICH (i801) driver is also needed for this kernel. Add LEDS_CLASS to config since the driver makes les_classdev_*() calls: ERROR: "led_classdev_register" [drivers/input/misc/apanel.ko] undefined! ERROR: "__led_classdev_unregister" [drivers/input/misc/apanel.ko] undefined! Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
-
Josef Bacik authored
The "resize" option won't be noticed as it comes after the NULL option, so if you try to mount (or in this case remount) with that option it won't be recognized. Signed-off-by:
Josef Bacik <jbacik@redhat.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by:
-
Nishanth Aravamudan authored
Adam Litke noticed that currently we grow the hugepage pool independent of any cpuset the running process may be in, but when shrinking the pool, the cpuset is checked. This leads to inconsistency when shrinking the pool in a restricted cpuset -- an administrator may have been able to grow the pool on a node restricted by a containing cpuset, but they cannot shrink it there. There are two options: either prevent growing of the pool outside of the cpuset or allow shrinking outside of the cpuset. >From previous discussions on linux-mm, /proc/sys/vm/nr_hugepages is an administrative interface that should not be restricted by cpusets. So allow shrinking the pool by removing pages from nodes outside of current's cpuset. Signed-off-by:
Nishanth Aravamudan <nacc@us.ibm.com> Acked-by:
Adam Litke <agl@us.ibm.com> Cc: William Irwin <wli@holomorphy.com> Cc: Lee Schermerhorn <Lee.Schermerhonr@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Paul Jackson <pj@sgi.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by:
-
Adam Litke authored
A hugetlb reservation may be inadequately backed in the event of racing allocations and frees when utilizing surplus huge pages. Consider the following series of events in processes A and B: A) Allocates some surplus pages to satisfy a reservation B) Frees some huge pages A) A notices the extra free pages and drops hugetlb_lock to free some of its surplus pages back to the buddy allocator. B) Allocates some huge pages A) Reacquires hugetlb_lock and returns from gather_surplus_huge_pages() Avoid this by commiting the reservation after pages have been allocated but before dropping the lock to free excess pages. For parity, release the reservation in return_unused_surplus_pages(). This patch also corrects the cpuset_mems_nr() error path in hugetlb_acct_memory(). If the cpuset check fails, uncommit the reservation, but also be sure to return any surplus huge pages that may have been allocated to back the failed reservation. Thanks to Andy Whitcroft for discovering this. Signed-off-by: -
K.Tanaka authored
This message describes another issue about md RAID10 found by testing the 2.6.24 md RAID10 using new scsi fault injection framework. Abstract: When a scsi error results in disabling a disk during RAID10 recovery, the resync threads of md RAID10 could stall. This case, the raid array has already been broken and it may not matter. But I think stall is not preferable. If it occurs, even shutdown or reboot will fail because of resource busy. The deadlock mechanism: The r10bio_s structure has a "remaining" member to keep track of BIOs yet to be handled when recovering. The "remaining" counter is incremented when building a BIO in sync_request() and is decremented when finish a BIO in end_sync_write(). If building a BIO fails for some reasons in sync_request(), the "remaining" should be decremented if it has already been incremented. I found a case where this decrement is forgotten. This causes a md_do_sync() deadlock because md_do_sync() waits for md_done_sync() called by end_sync_write(), but end_sync_write() never calls md_done_sync() because of the "remaining" counter mismatch. For example, this problem would be reproduced in the following case: Personalities : [raid10] md0 : active raid10 sdf1[4] sde1[5](F) sdd1[2] sdc1[1] sdb1[6](F) 3919616 blocks 64K chunks 2 near-copies [4/2] [_UU_] [>....................] recovery = 2.2% (45376/1959808) finish=0.7min speed=45376K/sec This case, sdf1 is recovering, sdb1 and sde1 are disabled. An additional error with detaching sdd will cause a deadlock. md0 : active raid10 sdf1[4] sde1[5](F) sdd1[6](F) sdc1[1] sdb1[7](F) 3919616 blocks 64K chunks 2 near-copies [4/1] [_U__] [=>...................] recovery = 5.0% (99520/1959808) finish=5.9min speed=5237K/sec 2739 ? S< 0:17 [md0_raid10] 28608 ? D< 0:00 [md0_resync] 28629 pts/1 Ss 0:00 bash 28830 pts/1 R+ 0:00 ps ax 31819 ? D< 0:00 [kjournald] The resync thread keeps working, but actually it is deadlocked. Patch: By this patch, the remaining counter will be decremented if needed. Signed-off-by:Neil Brown <neilb@suse.de> Signed-off-by:
-
NeilBrown authored
Thanks to K.Tanaka and the scsi fault injection framework, here is a fix for another possible deadlock in raid1/raid10 error handing. If a read request returns an error while a resync is happening and a resync request is pending, the attempt to fix the error will block until the resync progresses, and the resync will block until the read request completes. Thus a deadlock. This patch fixes the problem. Cc: "K.Tanaka" <k-tanaka@ce.jp.nec.com> Signed-off-by:
-
Keld Simonsen authored
This patch changes the disk to be read for layout "far > 1" to always be the disk with the lowest block address. Thus the chunks to be read will always be (for a fully functioning array) from the first band of stripes, and the raid will then work as a raid0 consisting of the first band of stripes. Some advantages: The fastest part which is the outer sectors of the disks involved will be used. The outer blocks of a disk may be as much as 100 % faster than the inner blocks. Average seek time will be smaller, as seeks will always be confined to the first part of the disks. Mixed disks with different performance characteristics will work better, as they will work as raid0, the sequential read rate will be number of disks involved times the IO rate of the slowest disk. If a disk is malfunctioning, the first disk which is working, and has the lowest block address for the logical block will be used. Signed-off-by:
Keld Simonsen <keld@dkuug.dk> Signed-off-by:
-
NeilBrown authored
When we access attributes of an rdev (component device on an md array) through sysfs, we really need to lock the array against concurrent changes. We currently do that when we change an attribute, but not when we read an attribute. We need to lock when reading as well else rdev->mddev could become NULL while we are accessing it. So add appropriate locking (mddev_lock) to rdev_attr_show. rdev_size_store requires some extra care as well as it needs to unlock the mddev while scanning other mddevs for overlapping regions. We currently assume that rdev->mddev will still be unchanged after the scan, but that cannot be certain. So take a copy of rdev->mddev for use at the end of the function. Signed-off-by:
-
NeilBrown authored
A resync/reshape/recovery thread will refuse to progress when the array is marked read-only. So whenever it mark it not read-only, it is important to wake up thread resync thread. There is one place we didn't do this. The problem manifests if the start_ro module parameters is set, and a raid5 array that is in the middle of a reshape (restripe) is started. The array will initially be semi-read-only (meaning it acts like it is readonly until the first write). So the reshape will not proceed. On the first write, the array will become read-write, but the reshape will not be started, and there is no event which will ever restart that thread. Signed-off-by:
-
NeilBrown authored
When a raid1 array is stopped, all components currently get added to the list for auto-detection. However we should really only add components that were found by autodetection in the first place. So add a flag to record that information, and use it. Signed-off-by:
-
NeilBrown authored
Make sure the data doesn't start before the end of the superblock when the superblock is at the start of the device. Signed-off-by:
-
NeilBrown authored
On an md array with a write-intent bitmap, a thread wakes up every few seconds and scans the bitmap looking for work to do. If the array is idle, there will be no work to do, but a lot of scanning is done to discover this. So cache the fact that the bitmap is completely clean, and avoid scanning the whole bitmap when the cache is known to be clean. Signed-off-by:
-
NeilBrown authored
When handling a read error, we freeze the array to stop any other IO while attempting to over-write with correct data. This is done in the raid1d(raid10d) thread and must wait for all submitted IO to complete (except for requests that failed and are sitting in the retry queue - these are counted in ->nr_queue and will stay there during a freeze). However write requests need attention from raid1d as bitmap updates might be required. This can cause a deadlock as raid1 is waiting for requests to finish that themselves need attention from raid1d. So we create a new function 'flush_pending_writes' to give that attention, and call it in freeze_array to be sure that we aren't waiting on raid1d. Thanks to "K.Tanaka" <k-tanaka@ce.jp.nec.com> for finding and reporting this problem. Cc: "K.Tanaka" <k-tanaka@ce.jp.nec.com> Signed-off-by:
-
FUJITA Tomonori authored
Make PARISC's two IOMMU implementations not allocate a memory area spanning LLD's segment boundary. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Grant Grundler <grundler@parisc-linux.org> Signed-off-by:
-
FUJITA Tomonori authored
This adds struct device argument to sba_alloc_range and ccio_alloc_range, a preparation for modifications to fix the IOMMU segment boundary problem. This change enables ccio_alloc_range to access to LLD's segment boundary limits. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
-
FUJITA Tomonori authored
iommu_is_span_boundary is used internally in the IOMMU helper (lib/iommu-helper.c), a primitive function that judges whether a memory area spans LLD's segment boundary or not. It's difficult to convert some IOMMUs to use the IOMMU helper but iommu_is_span_boundary is still useful for them. So this patch exports it. This is needed for the parisc iommu fixes. Signed-off-by:
-
Kyle McMartin authored
After a quick glance at the code, we're getting the DEBUG_SHIRQ spurious interrupt before we have the adapter template filled in. Real interrupts appear to be turned on by fcpci*_init(), so move request_irq until just before that. Signed-off-by:
Kyle McMartin <kmcmartin@redhat.com> Cc: Karsten Keil <kkeil@suse.de> Signed-off-by:
-
Michael Halcrow authored
When the page is not up to date, ecryptfs_prepare_write() should be acting much like ecryptfs_readpage(). This includes the painfully obvious step of actually decrypting the page contents read from the lower encrypted file. Note that this patch resolves a bug in eCryptfs in 2.6.24 that one can produce with these steps: # mount -t ecryptfs /secret /secret # echo "abc" > /secret/file.txt # umount /secret # mount -t ecryptfs /secret /secret # echo "def" >> /secret/file.txt # cat /secret/file.txt Without this patch, the resulting data returned from cat is likely to be something other than "abc\ndef\n". (Thanks to Benedikt Driessen for reporting this.) Signed-off-by:
Michael Halcrow <mhalcrow@us.ibm.com> Cc: Benedikt Driessen <bdriessen@escrypt.com> Cc: <stable@kernel.org> Signed-off-by:
-
Jesper Nilsson authored
Last commit for unistd was not correct, it only had a partial update of syscall numbers for __NR_timerfd_settime and __NR_timerfd_gettime. Also, NR_syscalls was not incremented for the new syscalls. Signed-off-by:
Jesper Nilsson <jesper.nilsson@axis.com> Cc: Mikael Starvik <mikael.starvik@axis.com> Signed-off-by:
-
Jesper Nilsson authored
Function __copy_user_zeroing in arch/lib/usercopy.c had the wrong parameter set as __user, and in include/asm-cris/uaccess.h, it was not set at all for some of the calling functions. This will cut the number of warnings quite dramatically when using sparse. While we're here, remove useless CVS log and correct confusing typo. Signed-off-by:
-
Henrique de Moraes Holschuh authored
I used the wrong return convention on hotkey_get_tablet_mode(), breaking a lot of stuff. Bad Henrique! Fix it to return the status in the parameter-by-reference, and IO status on the function return value. Duh. Signed-off-by:
Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: Zdenek Kabelac <zdenek.kabelac@gmail.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Lukas Hejtmanek <xhejtman@ics.muni.cz> Cc: Len Brown <lenb@kernel.org> Signed-off-by:
-
Julia Lawall authored
In commit e6bafba5 ("wmi: (!x & y) strikes again"), a bug was fixed that involved converting !x & y to !(x & y). The code below shows the same pattern, and thus should perhaps be fixed in the same way. This is not tested and clearly changes the semantics, so it is only something to consider. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression E1,E2; @@ ( !E1 & !E2 | - !E1 & E2 + !(E1 & E2) ) // </smpl> Signed-off-by:
Julia Lawall <julia@diku.dk> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Jan Kara <jack@ucw.cz> Signed-off-by:
-
Julia Lawall authored
In commit e6bafba5 ("wmi: (!x & y) strikes again"), a bug was fixed that involved converting !x & y to !(x & y). The code below shows the same pattern, and thus should perhaps be fixed in the same way. This is not tested and clearly changes the semantics, so it is only something to consider. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression E1,E2; @@ ( !E1 & !E2 | - !E1 & E2 + !(E1 & E2) ) // </smpl> Signed-off-by:
-
Julia Lawall authored
In commit e6bafba5 ("wmi: (!x & y) strikes again"), a bug was fixed that involved converting !x & y to !(x & y). The code below shows the same pattern, and thus should perhaps be fixed in the same way. This is not tested and clearly changes the semantics, so it is only something to consider. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression E1,E2; @@ ( !E1 & !E2 | - !E1 & E2 + !(E1 & E2) ) // </smpl> Signed-off-by:
-
Julia Lawall authored
In commit e6bafba5 ("wmi: (!x & y) strikes again"), a bug was fixed that involved converting !x & y to !(x & y). The code below shows the same pattern, and thus should perhaps be fixed in the same way. This is not tested and clearly changes the semantics, so it is only something to consider. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression E1,E2; @@ ( !E1 & !E2 | - !E1 & E2 + !(E1 & E2) ) // </smpl> Signed-off-by:
-
Hugh Dickins authored
While testing force_empty, during an exit_mmap, __mem_cgroup_remove_list called from mem_cgroup_uncharge_page oopsed on a NULL pointer in the lru list. I couldn't see what racing tasks on other cpus were doing, but surmise that another must have been in mem_cgroup_charge_common on the same page, between its unlock_page_cgroup and spin_lock_irqsave near done (thanks to that kzalloc which I'd almost changed to a kmalloc). Normally such a race cannot happen, the ref_cnt prevents it, the final uncharge cannot race with the initial charge. But force_empty buggers the ref_cnt, that's what it's all about; and thereafter forced pages are vulnerable to races such as this (just think of a shared page also mapped into an mm of another mem_cgroup than that just emptied). And remain vulnerable until they're freed indefinitely later. This patch just fixes the oops by moving the unlock_page_cgroups down below adding to and removing from the list (only possible given the previous patch); and while we're at it, we might as well make it an invariant that page->page_cgroup is always set while pc is on lru. But this behaviour of force_empty seems highly unsatisfactory to me: why have a ref_cnt if we always have to cope with it being violated (as in the earlier page migration patch). We may prefer force_empty to move pages to an orphan mem_cgroup (could be the root, but better not), from which other cgroups could recover them; we might need to reverse the locking again; but no time now for such concerns. Signed-off-by:
Hugh Dickins <hugh@veritas.com> Signed-off-by:
-
Hirokazu Takahashi authored
As for force_empty, though this may not be the main topic here, mem_cgroup_force_empty_list() can be implemented simpler. It is possible to make the function just call mem_cgroup_uncharge_page() instead of releasing page_cgroups by itself. The tip is to call get_page() before invoking mem_cgroup_uncharge_page(), so the page won't be released during this function. Kamezawa-san points out that by the time mem_cgroup_uncharge_page() uncharges, the page might have been reassigned to an lru of a different mem_cgroup, and now be emptied from that; but Hugh claims that's okay, the end state is the same as when it hasn't gone to another list. And once force_empty stops taking lock_page_cgroup within mz->lru_lock, mem_cgroup_move_lists() can be simplified to take mz->lru_lock directly while holding page_cgroup lock (but still has to use try_lock_page_cgroup). Signed-off-by:
Hirokazu Takahashi <taka@valinux.co.jp> Signed-off-by:
-
