Ondrej Kozina f5b0cba8f2 dm crypt: replace RCU read-side section with rwsem ... The lockdep splat below hints at a bug in RCU usage in dm-crypt that was introduced with commit c538f6ec9f ("dm crypt: add ability to use keys from the kernel key retention service"). The kernel keyring function user_key_payload() is in fact a wrapper for rcu_dereference_protected() which must not be called with only rcu_read_lock() section mark. Unfortunately the kernel keyring subsystem doesn't currently provide an interface that allows the use of an RCU read-side section. So for now we must drop RCU in favour of rwsem until a proper function is made available in the kernel keyring subsystem. =============================== [ INFO: suspicious RCU usage. ] 4.10.0-rc5 #2 Not tainted ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by cryptsetup/6464: #0: (&md->type_lock){+.+.+.}, at: [<ffffffffa02472a2>] dm_lock_md_type+0x12/0x20 [dm_mod] #1: (rcu_read_lock){......}, at: [<ffffffffa02822f8>] crypt_set_key+0x1d8/0x4b0 [dm_crypt] stack backtrace: CPU: 1 PID: 6464 Comm: cryptsetup Not tainted 4.10.0-rc5 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014 Call Trace: dump_stack+0x67/0x92 lockdep_rcu_suspicious+0xc5/0x100 crypt_set_key+0x351/0x4b0 [dm_crypt] ? crypt_set_key+0x1d8/0x4b0 [dm_crypt] crypt_ctr+0x341/0xa53 [dm_crypt] dm_table_add_target+0x147/0x330 [dm_mod] table_load+0x111/0x350 [dm_mod] ? retrieve_status+0x1c0/0x1c0 [dm_mod] ctl_ioctl+0x1f5/0x510 [dm_mod] dm_ctl_ioctl+0xe/0x20 [dm_mod] do_vfs_ioctl+0x8e/0x690 ? ____fput+0x9/0x10 ? task_work_run+0x7e/0xa0 ? trace_hardirqs_on_caller+0x122/0x1b0 SyS_ioctl+0x3c/0x70 entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x7f392c9a4ec7 RSP: 002b:00007ffef6383378 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffef63830a0 RCX: 00007f392c9a4ec7 RDX: 000000000124fcc0 RSI: 00000000c138fd09 RDI: 0000000000000005 RBP: 00007ffef6383090 R08: 00000000ffffffff R09: 00000000012482b0 R10: 2a28205d34383336 R11: 0000000000000246 R12: 00007f392d803a08 R13: 00007ffef63831e0 R14: 0000000000000000 R15: 00007f392d803a0b Fixes: c538f6ec9f ("dm crypt: add ability to use keys from the kernel key retention service") Reported-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Ondrej Kozina <okozina@redhat.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>		2017-02-03 10:26:14 -05:00
..
bcache
persistent-data
bitmap.c
bitmap.h
dm-bio-prison.c
dm-bio-prison.h
dm-bio-record.h
dm-bufio.c
dm-bufio.h
dm-builtin.c
dm-cache-block-types.h
dm-cache-metadata.c
dm-cache-metadata.h
dm-cache-policy-cleaner.c
dm-cache-policy-internal.h
dm-cache-policy-smq.c
dm-cache-policy.c
dm-cache-policy.h
dm-cache-target.c
dm-core.h
dm-crypt.c
dm-delay.c
dm-era-target.c
dm-exception-store.c
dm-exception-store.h
dm-flakey.c
dm-io.c
dm-ioctl.c
dm-kcopyd.c
dm-linear.c
dm-log-userspace-base.c
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log-writes.c
dm-log.c
dm-mpath.c
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c
dm-raid1.c
dm-raid.c
dm-region-hash.c
dm-round-robin.c
dm-rq.c
dm-rq.h
dm-service-time.c
dm-snap-persistent.c
dm-snap-transient.c
dm-snap.c
dm-stats.c
dm-stats.h
dm-stripe.c
dm-switch.c
dm-sysfs.c
dm-table.c
dm-target.c
dm-thin-metadata.c
dm-thin-metadata.h
dm-thin.c
dm-uevent.c
dm-uevent.h
dm-verity-fec.c
dm-verity-fec.h
dm-verity-target.c
dm-verity.h
dm-zero.c
dm.c
dm.h
faulty.c
Kconfig
linear.c
linear.h
Makefile
md-cluster.c
md-cluster.h
md.c
md.h
multipath.c
multipath.h
raid0.c
raid0.h
raid1.c
raid1.h
raid5-cache.c
raid5.c
raid5.h
raid10.c
raid10.h