start_kernel(): bug: interrupts were enabled early
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From: Rabin Vincent on 25 Mar 2010 15:50 On latest git, I'm seeing "start_kernel(): bug: interrupts were enabled early" messages on ARM (sample log below). This appears to be caused by: start_kernel -> radix_tree_init -> kmem_cache_create (slub) -> down_write -> __down_write (lib/rwsem-spinlock.c) -> spin_unlock_irq radix_tree_init was moved earlier by: commit 773e3eb7b81e5ba13b5155dfb3bb75b8ce37f8f9 Author: Yinghai Lu <yinghai(a)kernel.org> Date: Wed Feb 10 01:20:33 2010 -0800 init: Move radix_tree_init() early Prepare for using radix trees in early_irq_init(). Signed-off-by: Yinghai Lu <yinghai(a)kernel.org> LKML-Reference: <1265793639-15071-30-git-send-email-yinghai(a)kernel.org> Signed-off-by: H. Peter Anvin <hpa(a)zytor.com> Rabin --- Uncompressing Linux... done, booting the kernel. Linux version 2.6.34-rc2-00184-g01e7770 (rabin(a)debian) (gcc version 4.4.1 (Sourcery G++ Lite 2009q3-67) ) #5 Fri Mar 26 00:56:33 IST 2010 CPU: ARMv7 Processor [410fc080] revision 0 (ARMv7), cr=10c03c7f CPU: VIPT nonaliasing data cache, VIPT nonaliasing instruction cache Machine: ARM-RealView PB-A8 Ignoring unrecognised tag 0x00000000 bootconsole [earlycon0] enabled Memory policy: ECC disabled, Data cache writeback Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512 Kernel command line: earlyprintk mem=128M console=ttyAMA0 root=/dev/ram0 init=/linuxrc PID hash table entries: 512 (order: -1, 2048 bytes) Dentry cache hash table entries: 16384 (order: 4, 65536 bytes) Inode-cache hash table entries: 8192 (order: 3, 32768 bytes) Memory: 128MB = 128MB total Memory: 123916k/123916k available, 7156k reserved, 0K highmem Virtual kernel memory layout: vector : 0xffff0000 - 0xffff1000 ( 4 kB) fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB) DMA : 0xffc00000 - 0xffe00000 ( 2 MB) vmalloc : 0xc8800000 - 0xf8000000 ( 760 MB) lowmem : 0xc0000000 - 0xc8000000 ( 128 MB) modules : 0xbf000000 - 0xc0000000 ( 16 MB) .init : 0xc0008000 - 0xc0331000 (3236 kB) .text : 0xc0331000 - 0xc040b000 ( 872 kB) .data : 0xc040c000 - 0xc0418180 ( 49 kB) SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 Hierarchical RCU implementation. RCU-based detection of stalled CPUs is enabled. NR_IRQS:96 start_kernel(): bug: interrupts were enabled early Calibrating delay loop... 419.43 BogoMIPS (lpj=2097152) Mount-cache hash table entries: 512 CPU: Testing write buffer coherency: ok devtmpfs: initialized Serial: AMBA PL011 UART driver dev:uart0: ttyAMA0 at MMIO 0x10009000 (irq = 44) is a AMBA/PL011 console [ttyAMA0] enabled, bootconsole disabled console [ttyAMA0] enabled, bootconsole disabled dev:uart1: ttyAMA1 at MMIO 0x1000a000 (irq = 45) is a AMBA/PL011 dev:uart2: ttyAMA2 at MMIO 0x1000b000 (irq = 46) is a AMBA/PL011 fpga:uart3: ttyAMA3 at MMIO 0x1000c000 (irq = 47) is a AMBA/PL011 Switching to clocksource timer3 Unpacking initramfs... Freeing initrd memory: 1680K VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 0 Freeing init memory: 3236K -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrew Morton on 31 Mar 2010 16:50 On Fri, 26 Mar 2010 01:11:00 +0530 Rabin Vincent <rabin(a)rab.in> wrote: > On latest git, I'm seeing "start_kernel(): bug: interrupts were enabled > early" messages on ARM (sample log below). > > This appears to be caused by: > > start_kernel -> radix_tree_init -> kmem_cache_create (slub) -> > down_write -> __down_write (lib/rwsem-spinlock.c) -> spin_unlock_irq > > radix_tree_init was moved earlier by: > > commit 773e3eb7b81e5ba13b5155dfb3bb75b8ce37f8f9 > Author: Yinghai Lu <yinghai(a)kernel.org> > Date: Wed Feb 10 01:20:33 2010 -0800 > > init: Move radix_tree_init() early > > Prepare for using radix trees in early_irq_init(). > > Signed-off-by: Yinghai Lu <yinghai(a)kernel.org> > LKML-Reference: <1265793639-15071-30-git-send-email-yinghai(a)kernel.org> > Signed-off-by: H. Peter Anvin <hpa(a)zytor.com> > That's going to be hard to fix. Once upon a time, enabling interrupts too early in boot would kill powerpc boxes stone dead. From the lack of noise I assume that this is not happening in current kernels for some reason. We have two checks in start_kernel(): if (!irqs_disabled()) { printk(KERN_WARNING "start_kernel(): bug: interrupts were " "enabled *very* early, fixing it\n"); local_irq_disable(); } rcu_init(); radix_tree_init(); /* init some links before init_ISA_irqs() */ early_irq_init(); init_IRQ(); prio_tree_init(); init_timers(); hrtimers_init(); softirq_init(); timekeeping_init(); time_init(); profile_init(); if (!irqs_disabled()) printk(KERN_CRIT "start_kernel(): bug: interrupts were " "enabled early\n"); perhaps the second one isn't needed? Perhaps no architecture requires that local interrupts be disabled across the above initialisations? I'll ask Rafael and Maciej to track this as a post-2.6.33 regression. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Yinghai Lu on 31 Mar 2010 16:50 On 03/31/2010 01:40 PM, Andrew Morton wrote: > On Fri, 26 Mar 2010 01:11:00 +0530 > Rabin Vincent <rabin(a)rab.in> wrote: > >> > On latest git, I'm seeing "start_kernel(): bug: interrupts were enabled >> > early" messages on ARM (sample log below). >> > >> > This appears to be caused by: >> > >> > start_kernel -> radix_tree_init -> kmem_cache_create (slub) -> >> > down_write -> __down_write (lib/rwsem-spinlock.c) -> spin_unlock_irq >> > >> > radix_tree_init was moved earlier by: >> > >> > commit 773e3eb7b81e5ba13b5155dfb3bb75b8ce37f8f9 >> > Author: Yinghai Lu <yinghai(a)kernel.org> >> > Date: Wed Feb 10 01:20:33 2010 -0800 >> > >> > init: Move radix_tree_init() early >> > >> > Prepare for using radix trees in early_irq_init(). >> > >> > Signed-off-by: Yinghai Lu <yinghai(a)kernel.org> >> > LKML-Reference: <1265793639-15071-30-git-send-email-yinghai(a)kernel.org> >> > Signed-off-by: H. Peter Anvin <hpa(a)zytor.com> >> > > That's going to be hard to fix. > > Once upon a time, enabling interrupts too early in boot would kill > powerpc boxes stone dead. From the lack of noise I assume that this is > not happening in current kernels for some reason. > > We have two checks in start_kernel(): > > if (!irqs_disabled()) { > printk(KERN_WARNING "start_kernel(): bug: interrupts were " > "enabled *very* early, fixing it\n"); > local_irq_disable(); > } > rcu_init(); > radix_tree_init(); > /* init some links before init_ISA_irqs() */ > early_irq_init(); > init_IRQ(); > prio_tree_init(); > init_timers(); > hrtimers_init(); > softirq_init(); > timekeeping_init(); > time_init(); > profile_init(); > if (!irqs_disabled()) > printk(KERN_CRIT "start_kernel(): bug: interrupts were " > "enabled early\n"); > > perhaps the second one isn't needed? Perhaps no architecture requires > that local interrupts be disabled across the above initialisations? spin_unlock_irq from arm is different from other archs? YH -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Matthew Wilcox on 31 Mar 2010 17:10 On Wed, Mar 31, 2010 at 01:47:23PM -0700, Yinghai Lu wrote: > >> > This appears to be caused by: > >> > > >> > start_kernel -> radix_tree_init -> kmem_cache_create (slub) -> > >> > down_write -> __down_write (lib/rwsem-spinlock.c) -> spin_unlock_irq > >> > > > That's going to be hard to fix. > > > spin_unlock_irq from arm is different from other archs? Not all arches use lib/rwsem-spinlock.c. In particular, x86 doesn't when X86_XADD is set. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrew Morton on 31 Mar 2010 17:10
On Wed, 31 Mar 2010 13:47:23 -0700 Yinghai Lu <yinghai(a)kernel.org> wrote: > spin_unlock_irq from arm is different from other archs? No, spin_unlock_irq() unconditionally enables interrupts on all architectures. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |