On Sun, Jul 20, 2008 at 11:44:20AM -0400, Jeff Dike wrote: > On Mon, Jul 21, 2008 at 12:20:22AM +0900, Mattia Dongili wrote: > > it's not entirely clear to me why, but that patch fixes a segfault that > > I experience when booting uml 2.6.25 built with gcc-4.3 on a 2.6.25 > > host (I also applied your ICE workaround patch). > > Hmmm, get a stack trace from it and let's see what's going on. > > Presumably, you're not doing kernel development, just building a stock UML?
nope, not doing kernel development on that it's a stock UML, added patches are just small customizations for debian: http://svn.debian.org/viewsvn/pkg-uml/trunk/src/user-mode-linux/debian/patches/ patch #1 is not used, #2 and #3 are trivial changes. #4 is the gcc-4.3 ICE workaround and #5 is Jiaying's patch we are discussing. The configuration is this: http://svn.debian.org/viewsvn/pkg-uml/trunk/src/user-mode-linux/config.i386?rev=310&view=markup on top of this I enabled the debug info to be built: CONFIG_PRINTK_TIME=y CONFIG_DEBUG_KERNEL=y CONFIG_DEBUG_INFO=y CONFIG_FRAME_POINTER=y I also just reconfirmaed that with Jiaying's patch it doesn't happen. Program received signal SIGILL, Illegal instruction. 0x00000000 in ?? () (gdb) bt #0 0x00000000 in ?? () #1 0x080702e5 in __wake_up_common (q=0x16d50e88, mode=3, nr_exclusive=1, sync=0, key=0x0) at kernel/sched.c:4145 #2 0x08070323 in __wake_up_locked (q=0x16d50e88, mode=3) at kernel/sched.c:4174 #3 0x082556da in __down (sem=0x16d50e80) at lib/semaphore-sleepers.c:88 #4 0x0825401a in __down_failed () at arch/um/sys-i386/../../x86/lib/semaphore_32.S:42 #5 0x081072b7 in flush_commit_list (s=0x16dfba00, jl=0x16d50e80, flushall=1) at include/asm/arch/semaphore_32.h:99 #6 0x081077a3 in flush_async_commits (work=0x18936124) at fs/reiserfs/journal.c:3507 #7 0x08082a24 in run_workqueue (cwq=0x16ee9080) at kernel/workqueue.c:276 #8 0x08082cdf in worker_thread (__cwq=0x16ee9080) at kernel/workqueue.c:321 #9 0x0808538f in kthread (_create=0x17c679b4) at kernel/kthread.c:80 #10 0x08068f2b in run_kernel_thread (fn=0x8085347 <kthread>, arg=0x17c679b4, jmp_ptr=0x16e28bb4) at arch/um/os-Linux/process.c:267 #11 0x0805ae87 in new_thread_handler () at arch/um/kernel/process.c:151 #12 0x00000000 in ?? () (gdb) l 178 * area at compile-time.. 179 */ 180 static __always_inline void * __constant_c_memset(void * s, unsigned long c, size_t count) 181 { 182 int d0, d1; 183 __asm__ __volatile__( 184 "rep ; stosl\n\t" 185 "testb $2,%b3\n\t" 186 "je 1f\n\t" 187 "stosw\n" (gdb) up #1 0x080702e5 in __wake_up_common (q=0x16d50e88, mode=3, nr_exclusive=1, sync=0, key=0x0) at kernel/sched.c:4145 4145 if (curr->func(curr, mode, sync, key) && (gdb) print *curr $3 = {flags = 255, private = 0x0, func = 0, task_list = {next = 0x16d50e88, prev = 0x0}} it looks like there is not func here... (gdb) l 4140 wait_queue_t *curr, *next; 4141 4142 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 4143 unsigned flags = curr->flags; 4144 4145 if (curr->func(curr, mode, sync, key) && 4146 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) 4147 break; 4148 } 4149 } (gdb) up #2 0x08070323 in __wake_up_locked (q=0x16d50e88, mode=3) at kernel/sched.c:4174 4174 __wake_up_common(q, mode, 1, 0, NULL); (gdb) l 4169 /* 4170 * Same as __wake_up but called with the spinlock in wait_queue_head_t held. 4171 */ 4172 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode) 4173 { 4174 __wake_up_common(q, mode, 1, 0, NULL); 4175 } 4176 4177 /** 4178 * __wake_up_sync - wake up threads blocked on a waitqueue. (gdb) up #3 0x082556da in __down (sem=0x16d50e80) at lib/semaphore-sleepers.c:88 88 wake_up_locked(&sem->wait); (gdb) l 83 84 spin_lock_irqsave(&sem->wait.lock, flags); 85 tsk->state = TASK_UNINTERRUPTIBLE; 86 } 87 remove_wait_queue_locked(&sem->wait, &wait); 88 wake_up_locked(&sem->wait); 89 spin_unlock_irqrestore(&sem->wait.lock, flags); 90 tsk->state = TASK_RUNNING; 91 } 92 (gdb) print *sem $4 = {count = {counter = 5833}, sleepers = 0, wait = {lock = {raw_lock = {<No data fields>}}, task_list = {next = 0xf, prev = 0xf}}} Any other useful information I could provide? -- mattia :wq! ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
