On Sat, Oct 04, 2014 at 09:46:22PM +0800, Fengguang Wu wrote: > Hi Peter, > > 0day kernel testing robot got the below dmesg and the first bad commit is > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git perf/core > > commit a54b3e27e27c1bb6d2610eade895c04934c2667e > Author: Peter Zijlstra <pet...@infradead.org> > AuthorDate: Wed Sep 24 13:48:42 2014 +0200 > Commit: Peter Zijlstra <pet...@infradead.org> > CommitDate: Thu Oct 2 23:11:50 2014 +0200 > > perf: improve perf_sample_data struct layout > > This patch reorders fields in the perf_sample_data > struct in order to minimize the number of cachelines > touched in perf_sample_data_init(). It also removes > some intializations which are redundant with the > code in kernel/events/core.c > > Cc: mi...@elte.hu > Cc: a...@linux.intel.com > Cc: jo...@redhat.com > Cc: a...@redhat.com > Cc: cebbert.l...@gmail.com > Cc: pet...@infradead.org > > Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> > Link: > http://lkml.kernel.org/r/1411559322-16548-7-git-send-email-eran...@google.com >
> [ 267.547006] debug: unmapping init [mem 0xc28f9000-0xc2b03fff] > [ 267.694378] random: init urandom read with 4 bits of entropy available > [ 279.465522] sock: process `trinity-main' is using obsolete setsockopt > SO_BSDCOMPAT > [ 285.269144] BUG: unable to handle kernel NULL pointer dereference at > 00000085 > [ 285.273002] IP: [<c11259a1>] perf_prepare_sample+0x33e/0x496 > [ 285.276062] *pde = 00000000 > [ 285.279106] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 285.279106] Modules linked in: > [ 285.279106] CPU: 1 PID: 1583 Comm: trinity-main Not tainted > 3.17.0-rc4-00210-ga54b3e2 #1 > [ 285.279106] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.7.5-20140531_083030-gandalf 04/01/2014 > [ 285.279106] task: c9475e80 ti: c9670000 task.ti: c9670000 > [ 285.279106] EIP: 0060:[<c11259a1>] EFLAGS: 00010046 CPU: 1 > [ 285.279106] EIP is at perf_prepare_sample+0x33e/0x496 > [ 285.279106] EAX: 00000000 EBX: 00000000 ECX: 00000049 EDX: 00000000 > [ 285.279106] ESI: cfd71c40 EDI: cfd71b84 EBP: cfd71b58 ESP: cfd71b34 > [ 285.279106] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 > [ 285.279106] CR0: 80050033 CR2: 00000085 CR3: 095b4000 CR4: 000006d0 > [ 285.279106] DR0: 41000043 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 285.279106] DR6: ffff0ff0 DR7: 00010602 Could you try the below patch to confirm it works? > This script may reproduce the error. > > ---------------------------------------------------------------------------- > #!/bin/bash > > kernel=$1 > initrd=quantal-core-i386.cgz > > wget --no-clobber > https://github.com/fengguang/reproduce-kernel-bug/raw/master/initrd/$initrd > > kvm=( > qemu-system-x86_64 > -cpu kvm64 > -enable-kvm > -kernel $kernel > -initrd $initrd > -m 320 > -smp 2 > -net nic,vlan=1,model=e1000 > -net user,vlan=1 > -boot order=nc > -no-reboot > -watchdog i6300esb > -rtc base=localtime > -serial stdio > -display none > -monitor null > ) > > append=( > hung_task_panic=1 > earlyprintk=ttyS0,115200 > debug > apic=debug > sysrq_always_enabled > rcupdate.rcu_cpu_stall_timeout=100 > panic=-1 > softlockup_panic=1 > nmi_watchdog=panic > oops=panic > load_ramdisk=2 > prompt_ramdisk=0 > console=ttyS0,115200 > console=tty0 > vga=normal > root=/dev/ram0 > rw > drbd.minor_count=8 > ) > > "${kvm[@]}" --append "${append[*]}" > ---------------------------------------------------------------------------- What is lacking is the actual .config. Also the times above (~285 seconds) seem to suggest userspace needs to do something ? I tried with i386-defconfig and the above receptie gives me: ... [ 4.887413] tsc: Refined TSC clocksource calibration: 2693.765 MHz [ 5.257469] hwclock (874) used greatest stack depth: 6624 bytes left [ 5.299754] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input3 [ 5.911225] Switched to clocksource tsc [ 6.613714] init: Failed to create pty - disabling logging for job [ 6.615490] init: Temporary process spawn error: No space left on device [ 8.058431] initctl (926) used greatest stack depth: 6192 bytes left [ 9.084036] init: plymouth-log main process (940) terminated with status 1 Kernel tests: Boot OK! [ 71.302525] reboot: Restarting system Which I take is 'good', right? --- --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4953,12 +4953,13 @@ void perf_prepare_sample(struct perf_eve header->size += size; } + if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) + perf_sample_regs_user(&data->regs_user, regs); + if (sample_type & PERF_SAMPLE_REGS_USER) { /* regs dump ABI info */ int size = sizeof(u64); - perf_sample_regs_user(&data->regs_user, regs); - if (data->regs_user.regs) { u64 mask = event->attr.sample_regs_user; size += hweight64(mask) * sizeof(u64); @@ -4974,15 +4975,11 @@ void perf_prepare_sample(struct perf_eve * in case new sample type is added, because we could eat * up the rest of the sample size. */ - struct perf_regs *uregs = &data->regs_user; u16 stack_size = event->attr.sample_stack_user; u16 size = sizeof(u64); - if (!uregs->abi) - perf_sample_regs_user(uregs, regs); - stack_size = perf_sample_ustack_size(stack_size, header->size, - uregs->regs); + data->regs_user.regs); /* * If there is something to dump, add space for the dump -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
