CONFIG_DEBUG_SPINLOCK only adds spinlock tests for SMP builds. The
attached patch adds runtime checks for uniprocessor builds.
Tested on i386/UP, but it should work on all platforms. It contains
runtime checks for:
- missing initialization
- recursive lock
- double unlock
- incorrect use of spin_is_locked() or spin_trylock() [both function
do not work as expected on uniprocessor builds]
The next step are checks for spinlock ordering mismatches.
Which other runtime checks are possible?
Tests for correct _irq usage are not possible, several drivers use
disable_irq().
-- Manfred
// $Header$ // Kernel Version: // VERSION = 2 // PATCHLEVEL = 5 // SUBLEVEL = 1 // EXTRAVERSION =-pre5 --- 2.5/include/linux/spinlock.h Fri Oct 26 17:03:12 2001 +++ build-2.5/include/linux/spinlock.h Mon Dec 3 19:45:58 2001 @@ -37,12 +37,13 @@ #ifdef CONFIG_SMP #include <asm/spinlock.h> +#else -#elif !defined(spin_lock_init) /* !SMP and spin_lock_init not previously - defined (e.g. by including asm/spinlock.h */ - -#define DEBUG_SPINLOCKS 0 /* 0 == no debugging, 1 == maintain lock state, 2 == full debug */ - +#ifdef CONFIG_DEBUG_SPINLOCK +#define DEBUG_SPINLOCKS 2 /* 0 == no debugging, 1 == maintain lock state, 2 == full debug */ +#else +#define DEBUG_SPINLOCKS 0 +#endif #if (DEBUG_SPINLOCKS < 1) #define atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic) @@ -85,22 +86,101 @@ #else /* (DEBUG_SPINLOCKS >= 2) */ +#define SPINLOCK_MAGIC 0x1D244B3C typedef struct { + unsigned long magic; volatile unsigned long lock; volatile unsigned int babble; const char *module; + char *owner; + int oline; } spinlock_t; -#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 25, __BASE_FILE__ } +#define SPIN_LOCK_UNLOCKED (spinlock_t) { SPINLOCK_MAGIC, 0, 10, __FILE__ , NULL, 0} #include <linux/kernel.h> -#define spin_lock_init(x) do { (x)->lock = 0; } while (0) -#define spin_is_locked(lock) (test_bit(0,(lock))) -#define spin_trylock(lock) (!test_and_set_bit(0,(lock))) - -#define spin_lock(x) do {unsigned long __spinflags; save_flags(__spinflags); cli(); if ((x)->lock&&(x)->babble) {printk("%s:%d: spin_lock(%s:%p) already locked\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} (x)->lock = 1; restore_flags(__spinflags);} while (0) -#define spin_unlock_wait(x) do {unsigned long __spinflags; save_flags(__spinflags); cli(); if ((x)->lock&&(x)->babble) {printk("%s:%d: spin_unlock_wait(%s:%p) deadlock\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} restore_flags(__spinflags);} while (0) -#define spin_unlock(x) do {unsigned long __spinflags; save_flags(__spinflags); cli(); if (!(x)->lock&&(x)->babble) {printk("%s:%d: spin_unlock(%s:%p) not locked\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} (x)->lock = 0; restore_flags(__spinflags);} while (0) +#define spin_lock_init(x) \ + do { \ + (x)->magic = SPINLOCK_MAGIC; \ + (x)->lock = 0; \ + (x)->babble = 5; \ + (x)->module = __FILE__; \ + (x)->owner = NULL; \ + (x)->oline = 0; \ + } while (0) +#define CHECK_LOCK(x) \ + do { \ + if ((x)->magic != SPINLOCK_MAGIC) { \ + printk(KERN_ERR "%s:%d: spin_is_locked on uninitialized spinlock %p.\n", \ + __FILE__, __LINE__, (x)); \ + } \ + } while(0) +/* without debugging, spin_is_locked on UP always says + * FALSE. --> printk if already locked. */ +#define spin_is_locked(x) \ + ({ \ + CHECK_LOCK(x); \ + if ((x)->lock&&(x)->babble) { \ + printk("%s:%d: spin_is_locked(%s:%p) already locked by %s/%d\n", \ + __FILE__,__LINE__, (x)->module, \ + (x), (x)->owner, (x)->oline); \ + (x)->babble--; \ + } \ + 0; \ + }) + +/* without debugging, spin_trylock on UP always says + * TRUE. --> printk if already locked. */ +#define spin_trylock(x) \ + ({ \ + CHECK_LOCK(x); \ + if ((x)->lock&&(x)->babble) { \ + printk("%s:%d: spin_trylock(%s:%p) already locked by %s/%d\n", \ + __FILE__,__LINE__, (x)->module, \ + (x), (x)->owner, (x)->oline); \ + (x)->babble--; \ + } \ + (x)->lock = 1; \ + (x)->owner = __FILE__; \ + (x)->oline = __LINE__; \ + 1; \ + }) + +#define spin_lock(x) \ + do { \ + CHECK_LOCK(x); \ + if ((x)->lock&&(x)->babble) { \ + printk("%s:%d: spin_lock(%s:%p) already locked by %s/%d\n", \ + __FILE__,__LINE__, (x)->module, \ + (x), (x)->owner, (x)->oline); \ + (x)->babble--; \ + } \ + (x)->lock = 1; \ + (x)->owner = __FILE__; \ + (x)->oline = __LINE__; \ + } while (0) + +#define spin_unlock_wait(x) \ + do { \ + CHECK_LOCK(x); \ + if ((x)->lock&&(x)->babble) { \ + printk("%s:%d: spin_unlock_wait(%s:%p) owned by %s/%d\n", \ + __FILE__,__LINE__, (x)->module, (x), \ + (x)->owner, (x)->oline); \ + (x)->babble--; \ + }\ + } while (0) + +#define spin_unlock(x) \ + do { \ + CHECK_LOCK(x); \ + if (!(x)->lock&&(x)->babble) { \ + printk("%s:%d: spin_unlock(%s:%p) not locked\n", \ + __FILE__,__LINE__, (x)->module, (x));\ + (x)->babble--; \ + } \ + (x)->lock = 0; \ + } while (0) #endif /* DEBUG_SPINLOCKS */ --- 2.5/kernel/ksyms.c Mon Dec 3 18:30:08 2001 +++ build-2.5/kernel/ksyms.c Mon Dec 3 20:06:49 2001 @@ -381,10 +381,10 @@ EXPORT_SYMBOL(tq_timer); EXPORT_SYMBOL(tq_immediate); -#ifdef CONFIG_SMP /* Various random spinlocks we want to export */ EXPORT_SYMBOL(tqueue_lock); +#ifdef CONFIG_SMP /* Big-Reader lock implementation */ EXPORT_SYMBOL(__brlock_array); #ifndef __BRLOCK_USE_ATOMICS --- 2.5/Documentation/Configure.help Mon Dec 3 18:30:07 2001 +++ build-2.5/Documentation/Configure.help Mon Dec 3 20:31:40 2001 @@ -23565,8 +23565,10 @@ Spinlock debugging CONFIG_DEBUG_SPINLOCK - Say Y here and build SMP to catch missing spinlock initialization - and certain other kinds of spinlock errors commonly made. This is + Say Y here to add additional runtime checks into the spinlock + functions. On UP it detects missing initializations and simple + deadlocks. On SMP it finds missing initializations and certain other + kinds of spinlock errors commonly made, excluding deadlocks. This is best used in conjunction with the NMI watchdog so that spinlock deadlocks are also debuggable.
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This archive was generated by hypermail 2b29 : Fri Dec 07 2001 - 21:00:21 EST