lkml.org 
[lkml]   [2011]   [Aug]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    SubjectRe: [ANNOUNCE] 3.0.1-rt8 - Regression to 3.0-rt7
    Date
    Am Donnerstag, 11. August 2011, 14:41:38 schrieb Peter Zijlstra:
    > On Thu, 2011-08-11 at 14:02 +0200, Peter Zijlstra wrote:
    > > On Thu, 2011-08-11 at 13:30 +0200, Tim Sander wrote:
    > > > The error does not occur when configured with
    > > > CONFIG_PREEMPT_RT_FULL=y
    > > > but with
    > > > CONFIG_PREEMPT_RTB=y.
    > > > The same error also happens with
    > > > CONFIG_PREEMPT_LL=y. (A log is appended after the other log just
    > > > search for CONFIG_PREEMPT_LL
    > > > for starting point).
    > >
    > > Does the below (on top of -rt8) cure things for you? Shouldn't make a
    > > difference for PREEMPT_LL though, so maybe there's something else busted
    > > as well. But from what I can tell PREEMPT_BASE should be fine with such
    > > things disabling preemption..
    Yes it works for CONFIG_PREEMPT_RTB=y and as you say not for
    CONFIG_PREEMPT_LL=y.

    However with the following patches on top of rt8:

    diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
    index 44b3751..21ce185 100644
    --- a/include/linux/uaccess.h
    +++ b/include/linux/uaccess.h
    @@ -22,7 +22,7 @@ static inline void raw_pagefault_enable(void)
    preempt_check_resched();
    }

    -#ifndef CONFIG_PREEMPT_RT_FULL
    +#ifndef CONFIG_PREEMPT_RT_BASE
    static inline void pagefault_disable(void)
    {
    raw_pagefault_disable();
    diff --git a/mm/filemap.c b/mm/filemap.c
    index 71e2a1f..af63de3 100644
    --- a/mm/filemap.c
    +++ b/mm/filemap.c
    @@ -2040,7 +2040,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
    char *kaddr;
    size_t copied;

    - BUG_ON(!current->pagefault_disabled);
    + BUG_ON(!(in_atomic() || current->pagefault_disabled));
    kaddr = kmap_atomic(page, KM_USER0);
    if (likely(i->nr_segs == 1)) {
    int left;
    diff --git a/mm/memory.c b/mm/memory.c
    index cf71bd9..1b5a116 100644
    --- a/mm/memory.c
    +++ b/mm/memory.c
    @@ -3382,7 +3382,7 @@ unlock:
    return 0;
    }

    -#ifdef CONFIG_PREEMPT_RT_FULL
    +#ifdef CONFIG_PREEMPT_RT_BASE
    void pagefault_disable(void)
    {
    migrate_disable();
    i get the following bug:

    kernel BUG at kernel/posix-cpu-timers.c:1315!
    Unable to handle kernel NULL pointer dereference at virtual address 00000000
    pgd = c0004000
    [00000000] *pgd=00000000
    Internal error: Oops: 817 [#1] PREEMPT
    Modules linked in: i2c_imx(+) netx netx_reset dspload fpgaload mxc_nand(+) nand nand_ids nand_ecc
    CPU: 0 Not tainted (3.0.0-pmx-rt8-00009-g39305ab #167)
    PC is at __bug+0x24/0x30
    LR is at walk_stackframe+0x24/0x40
    pc : [<c002cbf0>] lr : [<c002cbb0>] psr: 60000113
    sp : c782ff40 ip : c782fe28 fp : c782ff4c
    r10: 00000001 r9 : 00000000 r8 : c78663c0
    r7 : c030463c r6 : c782e000 r5 : 00000000 r4 : c78663c0
    r3 : 00000000 r2 : 00000001 r1 : c782fe58 r0 : 00000034
    Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
    Control: 00c5387d Table: 87b70008 DAC: 00000017
    Process posixcputmr/0 (pid: 6, stack limit = 0xc782e268)
    Stack: (0xc782ff40 to 0xc7830000)
    ff40: c782ff8c c782ff50 c005a5c0 c002cbd8 00000000 c782ff54 c782ff54 00000000
    ff60: 00000000 c78663c0 00000000 c782e000 c030463c c78663c0 00000000 00000001
    ff80: c782ffbc c782ff90 c005a88c c005a594 00000000 c7817f28 00000000 c782ffcc
    ffa0: c005a800 00000000 00000000 00000000 c782fff4 c782ffc0 c00570f0 c005a80c
    ffc0: c7817f28 00000000 00000000 00000000 c782ffd0 c782ffd0 c7817f28 c0057064
    ffe0: c0040868 00000013 00000000 c782fff8 c0040868 c0057070 cccdcd6c ffdec890
    Backtrace:
    [<c002cbcc>] (__bug+0x0/0x30) from [<c005a5c0>] (__run_posix_cpu_timers+0x38/0x278)
    [<c005a588>] (__run_posix_cpu_timers+0x0/0x278) from [<c005a88c>] (posix_cpu_timers_thread+0x8c/0x124)
    [<c005a800>] (posix_cpu_timers_thread+0x0/0x124) from [<c00570f0>] (kthread+0x8c/0x94)
    [<c0057064>] (kthread+0x0/0x94) from [<c0040868>] (do_exit+0x0/0x2d8)
    r7:00000013 r6:c0040868 r5:c0057064 r4:c7817f28
    Code: e59f0010 e1a01003 eb086a88 e3a03000 (e5833000)
    ---[ end trace d632afeaa11559d4 ]---
    Otherwise the system boots and works

    Best regards
    Tim

    Hottinger Baldwin Messtechnik GmbH, Im Tiefen See 45, 64293 Darmstadt, Germany | www.hbm.com
    Registered as GmbH (German limited liability corporation) in the commercial register at the local court of Darmstadt, HRB 1147
    Company domiciled in Darmstadt | CEO: Andreas Huellhorst | Chairman of the board: James Charles Webster
    Als Gesellschaft mit beschraenkter Haftung eingetragen im Handelsregister des Amtsgerichts Darmstadt unter HRB 1147
    Sitz der Gesellschaft: Darmstadt | Geschaeftsfuehrung: Andreas Huellhorst | Aufsichtsratsvorsitzender: James Charles Webster
    The information in this email is confidential. It is intended solely for the addressee. If you are not the intended recipient, please let me know and delete this email.

    Die in dieser E-Mail enthaltene Information ist vertraulich und lediglich für den Empfaenger bestimmt. Sollten Sie nicht der eigentliche Empfaenger sein, informieren Sie mich bitte kurz und loeschen diese E-Mail.

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-08-11 18:07    [W:3.313 / U:0.396 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site