majianpeng 60aaf93385 md/raid5: Use conf->device_lock protect changing of multi-thread resources. ... When we change group_thread_cnt from sysfs entry, it can OOPS. The kernel messages are: [ 135.299021] BUG: unable to handle kernel NULL pointer dereference at (null) [ 135.299073] IP: [<ffffffff815188ab>] handle_active_stripes+0x32b/0x440 [ 135.299107] PGD 0 [ 135.299122] Oops: 0000 [#1] SMP [ 135.299144] Modules linked in: netconsole e1000e ptp pps_core [ 135.299188] CPU: 3 PID: 2225 Comm: md0_raid5 Not tainted 3.12.0+ #24 [ 135.299214] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080015 11/09/2011 [ 135.299255] task: ffff8800b9638f80 ti: ffff8800b77a4000 task.ti: ffff8800b77a4000 [ 135.299283] RIP: 0010:[<ffffffff815188ab>] [<ffffffff815188ab>] handle_active_stripes+0x32b/0x440 [ 135.299323] RSP: 0018:ffff8800b77a5c48 EFLAGS: 00010002 [ 135.299344] RAX: ffff880037bb5c70 RBX: 0000000000000000 RCX: 0000000000000008 [ 135.299371] RDX: ffff880037bb5cb8 RSI: 0000000000000001 RDI: ffff880037bb5c00 [ 135.299398] RBP: ffff8800b77a5d08 R08: 0000000000000001 R09: 0000000000000000 [ 135.299425] R10: ffff8800b77a5c98 R11: 00000000ffffffff R12: ffff880037bb5c00 [ 135.299452] R13: 0000000000000000 R14: 0000000000000000 R15: ffff880037bb5c70 [ 135.299479] FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 [ 135.299510] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 135.299532] CR2: 0000000000000000 CR3: 0000000001c0b000 CR4: 00000000000407e0 [ 135.299559] Stack: [ 135.299570] ffff8800b77a5c88 ffffffff8107383e ffff8800b77a5c88 ffff880037a64300 [ 135.299611] 000000000000ec08 ffff880037bb5cb8 ffff8800b77a5c98 ffffffffffffffd8 [ 135.299654] 000000000000ec08 ffff880037bb5c60 ffff8800b77a5c98 ffff8800b77a5c98 [ 135.299696] Call Trace: [ 135.299711] [<ffffffff8107383e>] ? __wake_up+0x4e/0x70 [ 135.299733] [<ffffffff81518f88>] raid5d+0x4c8/0x680 [ 135.299756] [<ffffffff817174ed>] ? schedule_timeout+0x15d/0x1f0 [ 135.299781] [<ffffffff81524c9f>] md_thread+0x11f/0x170 [ 135.299804] [<ffffffff81069cd0>] ? wake_up_bit+0x40/0x40 [ 135.299826] [<ffffffff81524b80>] ? md_rdev_init+0x110/0x110 [ 135.299850] [<ffffffff81069656>] kthread+0xc6/0xd0 [ 135.299871] [<ffffffff81069590>] ? kthread_freezable_should_stop+0x70/0x70 [ 135.299899] [<ffffffff81722ffc>] ret_from_fork+0x7c/0xb0 [ 135.299923] [<ffffffff81069590>] ? kthread_freezable_should_stop+0x70/0x70 [ 135.299951] Code: ff ff ff 0f 84 d7 fe ff ff e9 5c fe ff ff 66 90 41 8b b4 24 d8 01 00 00 45 31 ed 85 f6 0f 8e 7b fd ff ff 49 8b 9c 24 d0 01 00 00 <48> 3b 1b 49 89 dd 0f 85 67 fd ff ff 48 8d 43 28 31 d2 eb 17 90 [ 135.300005] RIP [<ffffffff815188ab>] handle_active_stripes+0x32b/0x440 [ 135.300005] RSP <ffff8800b77a5c48> [ 135.300005] CR2: 0000000000000000 [ 135.300005] ---[ end trace 504854e5bb7562ed ]--- [ 135.300005] Kernel panic - not syncing: Fatal exception This is because raid5d() can be running when the multi-thread resources are changed via system. We see need to provide locking. mddev->device_lock is suitable, but we cannot simple call alloc_thread_groups under this lock as we cannot allocate memory while holding a spinlock. So change alloc_thread_groups() to allocate and return the data structures, then raid5_store_group_thread_cnt() can take the lock while updating the pointers to the data structures. This fixes a bug introduced in 3.12 and so is suitable for the 3.12.x stable series. Fixes: b721420e87 Cc: stable@vger.kernel.org (3.12) Signed-off-by: Jianpeng Ma <majianpeng@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Shaohua Li <shli@kernel.org>		2013-11-19 15:19:18 +11:00
..
bcache	bcache: Fixed incorrect order of arguments to bio_alloc_bioset()	2013-10-23 07:55:36 +01:00
persistent-data	dm space map: optimise sm_ll_dec and sm_ll_inc	2013-08-23 09:02:14 -04:00
bitmap.c	sysfs: clean up sysfs_get_dirent()	2013-09-26 15:33:18 -07:00
bitmap.h	md/bitmap: record the space available for the bitmap in the superblock.	2012-05-22 13:55:34 +10:00
dm-bio-prison.c	dm: add cache target	2013-03-01 22:45:51 +00:00
dm-bio-prison.h	dm: add cache target	2013-03-01 22:45:51 +00:00
dm-bio-record.h
dm-bufio.c	drivers: convert shrinkers to new count/scan API	2013-09-10 18:56:32 -04:00
dm-bufio.h	dm bufio: prefetch	2012-03-28 18:41:29 +01:00
dm-cache-block-types.h	dm: add cache target	2013-03-01 22:45:51 +00:00
dm-cache-metadata.c	dm cache: replace memcpy with struct assignment	2013-05-10 14:37:18 +01:00
dm-cache-metadata.h	dm cache: policy ignore hints if generated by different version	2013-03-20 17:21:28 +00:00
dm-cache-policy-cleaner.c	dm cache: policy change version from string to integer set	2013-03-20 17:21:27 +00:00
dm-cache-policy-internal.h	dm cache: policy change version from string to integer set	2013-03-20 17:21:27 +00:00
dm-cache-policy-mq.c	dm cache: avoid conflicting remove_mapping() in mq policy	2013-08-16 15:56:51 -04:00
dm-cache-policy.c	dm cache: policy change version from string to integer set	2013-03-20 17:21:27 +00:00
dm-cache-policy.h	dm cache policy: fix description of lookup fn	2013-05-10 14:37:17 +01:00
dm-cache-target.c	dm cache: eliminate holes in cache structure	2013-08-23 09:02:14 -04:00
dm-crypt.c	dm: stop using WQ_NON_REENTRANT	2013-08-23 09:02:13 -04:00
dm-delay.c	dm: rename request variables to bios	2013-03-01 22:45:47 +00:00
dm-exception-store.c	dm: replace simple_strtoul	2012-07-27 15:07:59 +01:00
dm-exception-store.h
dm-flakey.c	dm flakey: correct ctr alloc failure mesg	2013-07-10 23:41:17 +01:00
dm-io.c	dm: add reserved_bio_based_ios module parameter	2013-09-23 10:42:24 -04:00
dm-ioctl.c	dm: add statistics support	2013-09-05 20:46:06 -04:00
dm-kcopyd.c	dm: stop using WQ_NON_REENTRANT	2013-08-23 09:02:13 -04:00
dm-linear.c	dm: rename request variables to bios	2013-03-01 22:45:47 +00:00
dm-log-userspace-base.c	Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux	2011-11-06 19:44:47 -08:00
dm-log-userspace-transfer.c	connector/userns: replace netlink uses of cap_raised() with capable()	2012-05-10 23:21:39 -04:00
dm-log-userspace-transfer.h
dm-log.c	dm: use memweight()	2012-07-30 17:25:16 -07:00
dm-mpath.c	dm: add reserved_rq_based_ios module parameter	2013-09-23 10:42:24 -04:00
dm-mpath.h
dm-path-selector.c	md: Add module.h to all files using it implicitly	2011-10-31 19:31:18 -04:00
dm-path-selector.h
dm-queue-length.c	dm: reject trailing characters in sccanf input	2012-03-28 18:41:26 +01:00
dm-raid1.c	dm: stop using WQ_NON_REENTRANT	2013-08-23 09:02:13 -04:00
dm-raid.c	MD: Remember the last sync operation that was performed	2013-06-26 12:38:24 +10:00
dm-region-hash.c	dm raid1: fix crash with mirror recovery and discard	2012-07-20 14:25:03 +01:00
dm-round-robin.c	dm: reject trailing characters in sccanf input	2012-03-28 18:41:26 +01:00
dm-service-time.c	dm: reject trailing characters in sccanf input	2012-03-28 18:41:26 +01:00
dm-snap-persistent.c	dm snapshot: fix data corruption	2013-10-16 03:17:47 +01:00
dm-snap-transient.c	md: Add in export.h for files using EXPORT_SYMBOL	2011-10-31 19:31:19 -04:00
dm-snap.c	dm-snapshot: fix performance degradation due to small hash size	2013-09-20 10:36:34 -04:00
dm-stats.c	dm stats: fix possible counter corruption on 32-bit systems	2013-09-18 14:41:06 -04:00
dm-stats.h	dm: add statistics support	2013-09-05 20:46:06 -04:00
dm-stripe.c	dm stripe: silence a couple sparse warnings	2013-09-06 11:36:01 -04:00
dm-switch.c	dm: add switch target	2013-07-10 23:41:19 +01:00
dm-sysfs.c
dm-table.c	dm ioctl: increase granularity of type_lock when loading table	2013-09-05 20:46:06 -04:00
dm-target.c	dm: allow error target to replace bio-based and request-based targets	2013-09-05 20:46:05 -04:00
dm-thin-metadata.c	dm thin: generate event when metadata threshold passed	2013-05-10 14:37:21 +01:00
dm-thin-metadata.h	dm thin: generate event when metadata threshold passed	2013-05-10 14:37:21 +01:00
dm-thin.c	dm thin: do not expose non-zero discard limits if discards disabled	2013-09-23 10:42:06 -04:00
dm-uevent.c	md: Add in export.h for files using EXPORT_SYMBOL	2011-10-31 19:31:19 -04:00
dm-uevent.h
dm-verity.c	dm verity: use __ffs and __fls	2013-07-10 23:41:17 +01:00
dm-zero.c	dm: rename request variables to bios	2013-03-01 22:45:47 +00:00
dm.c	dm: add reserved_bio_based_ios module parameter	2013-09-23 10:42:24 -04:00
dm.h	dm: add reserved_bio_based_ios module parameter	2013-09-23 10:42:24 -04:00
faulty.c	block: Add bio_end_sector()	2013-03-23 14:15:29 -07:00
Kconfig	dm: add switch target	2013-07-10 23:41:19 +01:00
linear.c	block: Add bio_end_sector()	2013-03-23 14:15:29 -07:00
linear.h	md/linear: typedef removal: linear_conf_t -> struct linear_conf	2011-10-11 16:48:54 +11:00
Makefile	dm: add statistics support	2013-09-05 20:46:06 -04:00
md.c	md: Convert use of typedef ctl_table to struct ctl_table	2013-11-19 15:19:18 +11:00
md.h	sysfs: clean up sysfs_get_dirent()	2013-09-26 15:33:18 -07:00
multipath.c	MD: change the parameter of md thread	2012-10-11 13:34:00 +11:00
multipath.h	md/multipath: typedef removal: multipath_conf_t -> struct mpconf	2011-10-11 16:48:57 +11:00
raid0.c	md: fix buglet in RAID5 -> RAID0 conversion.	2013-06-26 12:38:19 +10:00
raid0.h	md: add proper merge_bvec handling to RAID0 and Linear.	2012-03-19 12:46:39 +11:00
raid1.c	raid1: Rewrite the implementation of iobarrier.	2013-11-19 15:19:18 +11:00
raid1.h	raid1: Rewrite the implementation of iobarrier.	2013-11-19 15:19:18 +11:00
raid5.c	md/raid5: Use conf->device_lock protect changing of multi-thread resources.	2013-11-19 15:19:18 +11:00
raid5.h	raid5: relieve lock contention in get_active_stripe()	2013-11-19 15:18:22 +11:00
raid10.c	md: use MD_RECOVERY_INTR instead of kthread_should_stop in resync thread.	2013-11-19 15:19:17 +11:00
raid10.h	MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1)	2013-02-26 11:55:30 +11:00