Messages in this thread | | | Date | Fri, 20 Mar 2009 14:07:53 +0100 | From | Heiko Carstens <> | Subject | Re: [PATCH] lockdep: fix deadlock in lockdep_trace_alloc |
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On Fri, 20 Mar 2009 11:26:38 +0100 Peter Zijlstra <peterz@infradead.org> wrote:
> Heiko pointed out that checking for irqs_disabled() after we disable > them is quite pointless.. > > New patch below. > > --- > Subject: lockdep: fix deadlock in lockdep_trace_alloc > From: Peter Zijlstra <a.p.zijlstra@chello.nl> > Date: Fri Mar 20 11:24:21 CET 2009 > > Heiko reported that we grab the graph lock with irqs enabled. > > Fix this by providing the same wrapper as all other lockdep entry > functions have. > > Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > --- > kernel/lockdep.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > Index: linux-2.6/kernel/lockdep.c > =================================================================== > --- linux-2.6.orig/kernel/lockdep.c > +++ linux-2.6/kernel/lockdep.c > @@ -2258,7 +2258,7 @@ void trace_softirqs_off(unsigned long ip > debug_atomic_inc(&redundant_softirqs_off); > } > > -void lockdep_trace_alloc(gfp_t gfp_mask) > +static void __lockdep_trace_alloc(gfp_t gfp_mask) > { > struct task_struct *curr = current; > > @@ -2277,10 +2277,27 @@ void lockdep_trace_alloc(gfp_t gfp_mask) > if (!(gfp_mask & __GFP_FS)) > return; > > + mark_held_locks(curr, RECLAIM_FS); > +} > + > +static void check_flags(unsigned long flags); > + > +void lockdep_trace_alloc(gfp_t gfp_mask) > +{ > + unsigned long flags; > + > + if (unlikely(current->lockdep_recursion)) > + return; > + > if (DEBUG_LOCKS_WARN_ON(irqs_disabled())) > return; > > - mark_held_locks(curr, RECLAIM_FS); > + raw_local_irq_save(flags); > + check_flags(flags); > + current->lockdep_recursion = 1; > + __lockdep_trace_alloc(gfp_mask); > + current->lockdep_recursion = 0; > + raw_local_irq_restore(flags);
Hmm... still not working:
------------[ cut here ]------------ Badness at kernel/lockdep.c:2292 Modules linked in: CPU: 0 Not tainted 2.6.29-rc8-next-20090320-dirty #19 Process swapper (pid: 0, task: 000000000061ddf0, ksp: 0000000000678000) Krnl PSW : 0400000180000000 000000000007c784 (lockdep_trace_alloc+0xc0/0xf8) R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3 Krnl GPRS: 0000000000000003 0000000000fe0f18 0000000000000000 000000000000000f 0000000000667800 0000000000000000 0000000000000000 0000000000000000 000000003fe09f00 0000000000000020 000000003fe0fc00 0000000000677910 0000000000000020 0000000000432538 000000000007c76c 0000000000677910 Krnl Code: 000000000007c778: bf2f1000 icm %rr2,15,0(%rr1) 000000000007c77c: a774ffe8 brc 7,7c74c 000000000007c780: a7f40001 brc 15,7c782 >000000000007c784: a7f4ffe4 brc 15,7c74c 000000000007c788: a7c10010 tmll %rr12,16 000000000007c78c: a784ffd4 brc 8,7c734 000000000007c790: e32002e00004 lg %rr2,736 000000000007c796: 91082016 tm 22(%rr2),8 Call Trace: ([<0000000000677928>] init_thread_union+0x3928/0x4000) [<00000000000aaa48>] __alloc_pages_internal+0x354/0x570 [<00000000000db184>] cache_alloc_refill+0x41c/0x7ac [<00000000000db7fa>] kmem_cache_alloc+0x11a/0x150 [<00000000001fae3e>] idr_pre_get+0x92/0xcc [<00000000001faeac>] ida_pre_get+0x34/0xb4 [<00000000000e399a>] set_anon_super+0x3e/0x108 [<00000000000e46a8>] sget+0x3a4/0x47c [<00000000000e4fe8>] get_sb_single+0x48/0xec [<0000000000151d4c>] sysfs_get_sb+0x30/0x44 [<00000000000e3764>] vfs_kern_mount+0x68/0xfc [<00000000000e382c>] kern_mount_data+0x34/0x44 [<000000000068be74>] sysfs_init+0xb4/0xf4 [<000000000068aa82>] mnt_init+0xbe/0x264 [<000000000068a0f0>] vfs_caches_init+0xec/0x1a4 [<0000000000678dd4>] start_kernel+0x4dc/0x6dc [<0000000000012020>] _ehead+0x20/0x80 INFO: lockdep is turned off. Last Breaking-Event-Address: [<000000000007c780>] lockdep_trace_alloc+0xbc/0xf8
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