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| author | Stephen Boyd <sboyd@codeaurora.org> | 2012-12-20 08:39:48 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-20 22:50:16 +0100 |
| commit | fcc16882ac4532aaa644bff444f0c5d6228ba71e (patch) | |
| tree | 7104729ed7fd136a26ea47462e716410666aa1f6 | |
| parent | Merge tag 'iommu-updates-v3.8' of git://git.kernel.org/pub/scm/linux/kernel/g... (diff) | |
| download | linux-fcc16882ac4532aaa644bff444f0c5d6228ba71e.tar.xz linux-fcc16882ac4532aaa644bff444f0c5d6228ba71e.zip | |
lib: atomic64: Initialize locks statically to fix early users
The atomic64 library uses a handful of static spin locks to implement
atomic 64-bit operations on architectures without support for atomic
64-bit instructions.
Unfortunately, the spinlocks are initialized in a pure initcall and that
is too late for the vfs namespace code which wants to use atomic64
operations before the initcall is run.
This became a problem as of commit 8823c079ba71: "vfs: Add setns support
for the mount namespace".
This leads to BUG messages such as:
BUG: spinlock bad magic on CPU#0, swapper/0/0
lock: atomic64_lock+0x240/0x400, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
do_raw_spin_lock+0x158/0x198
_raw_spin_lock_irqsave+0x4c/0x58
atomic64_add_return+0x30/0x5c
alloc_mnt_ns.clone.14+0x44/0xac
create_mnt_ns+0xc/0x54
mnt_init+0x120/0x1d4
vfs_caches_init+0xe0/0x10c
start_kernel+0x29c/0x300
coming out early on during boot when spinlock debugging is enabled.
Fix this by initializing the spinlocks statically at compile time.
Reported-and-tested-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | lib/atomic64.c | 17 |
1 files changed, 5 insertions, 12 deletions
diff --git a/lib/atomic64.c b/lib/atomic64.c index 978537809d84..08a4f068e61e 100644 --- a/lib/atomic64.c +++ b/lib/atomic64.c @@ -31,7 +31,11 @@ static union { raw_spinlock_t lock; char pad[L1_CACHE_BYTES]; -} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp; +} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp = { + [0 ... (NR_LOCKS - 1)] = { + .lock = __RAW_SPIN_LOCK_UNLOCKED(atomic64_lock.lock), + }, +}; static inline raw_spinlock_t *lock_addr(const atomic64_t *v) { @@ -173,14 +177,3 @@ int atomic64_add_unless(atomic64_t *v, long long a, long long u) return ret; } EXPORT_SYMBOL(atomic64_add_unless); - -static int init_atomic64_lock(void) -{ - int i; - - for (i = 0; i < NR_LOCKS; ++i) - raw_spin_lock_init(&atomic64_lock[i].lock); - return 0; -} - -pure_initcall(init_atomic64_lock); |