From: Stephen Boyd <[email protected]> Subject: 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 (introduced by 8823c07 "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 [<c001af64>] (unwind_backtrace+0x0/0xf0) from [<c02c2010>] (do_raw_spin_lock+0x158/0x198) [<c02c2010>] (do_raw_spin_lock+0x158/0x198) from [<c04d89ec>] (_raw_spin_lock_irqsave+0x4c/0x58) [<c04d89ec>] (_raw_spin_lock_irqsave+0x4c/0x58) from [<c02cabf0>] (atomic64_add_return+0x30/0x5c) [<c02cabf0>] (atomic64_add_return+0x30/0x5c) from [<c0124564>] (alloc_mnt_ns.clone.14+0x44/0xac) [<c0124564>] (alloc_mnt_ns.clone.14+0x44/0xac) from [<c0124f4c>] (create_mnt_ns+0xc/0x54) [<c0124f4c>] (create_mnt_ns+0xc/0x54) from [<c06f31a4>] (mnt_init+0x120/0x1d4) [<c06f31a4>] (mnt_init+0x120/0x1d4) from [<c06f2d50>] (vfs_caches_init+0xe0/0x10c) [<c06f2d50>] (vfs_caches_init+0xe0/0x10c) from [<c06d4798>] (start_kernel+0x29c/0x300) [<c06d4798>] (start_kernel+0x29c/0x300) from [<80008078>] (0x80008078) coming out early on during boot when spinlock debugging is enabled. Fix this problem by initializing the spinlocks statically at compile time. Signed-off-by: Stephen Boyd <[email protected]> Reported-by: Vaibhav Bedia <[email protected]> Tested-by: Vaibhav Bedia <[email protected]> Cc: Eric W. Biederman <[email protected]> Tested-by: Tony Lindgren <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: David Miller <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- lib/atomic64.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff -puN lib/atomic64.c~lib-atomic64-initialize-locks-statically-to-fix-early-users lib/atomic64.c --- a/lib/atomic64.c~lib-atomic64-initialize-locks-statically-to-fix-early-users +++ a/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, l 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); _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
