61 lines
2.5 KiB
Diff
61 lines
2.5 KiB
Diff
Subject: printk: Disable migration instead of preemption
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From: Richard Weinberger <rw@linutronix.de>
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Date: Mon, 12 Dec 2011 14:35:56 +0100
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There is no need do disable preemption in vprintk(), disable_migrate()
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is sufficient. This fixes the following bug in -rt:
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[ 14.759233] BUG: sleeping function called from invalid context
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at /home/rw/linux-rt/kernel/rtmutex.c:645
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[ 14.759235] in_atomic(): 1, irqs_disabled(): 0, pid: 547, name: bash
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[ 14.759244] Pid: 547, comm: bash Not tainted 3.0.12-rt29+ #3
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[ 14.759246] Call Trace:
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[ 14.759301] [<ffffffff8106fade>] __might_sleep+0xeb/0xf0
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[ 14.759318] [<ffffffff810ad784>] rt_spin_lock_fastlock.constprop.9+0x21/0x43
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[ 14.759336] [<ffffffff8161fef0>] rt_spin_lock+0xe/0x10
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[ 14.759354] [<ffffffff81347ad1>] serial8250_console_write+0x81/0x121
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[ 14.759366] [<ffffffff8107ecd3>] __call_console_drivers+0x7c/0x93
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[ 14.759369] [<ffffffff8107ef31>] _call_console_drivers+0x5c/0x60
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[ 14.759372] [<ffffffff8107f7e5>] console_unlock+0x147/0x1a2
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[ 14.759374] [<ffffffff8107fd33>] vprintk+0x3ea/0x462
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[ 14.759383] [<ffffffff816160e0>] printk+0x51/0x53
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[ 14.759399] [<ffffffff811974e4>] ? proc_reg_poll+0x9a/0x9a
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[ 14.759403] [<ffffffff81335b42>] __handle_sysrq+0x50/0x14d
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[ 14.759406] [<ffffffff81335c8a>] write_sysrq_trigger+0x4b/0x53
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[ 14.759408] [<ffffffff81335c3f>] ? __handle_sysrq+0x14d/0x14d
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[ 14.759410] [<ffffffff81197583>] proc_reg_write+0x9f/0xbe
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[ 14.759426] [<ffffffff811497ec>] vfs_write+0xac/0xf3
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[ 14.759429] [<ffffffff8114a9b3>] ? fget_light+0x3a/0x9b
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[ 14.759431] [<ffffffff811499db>] sys_write+0x4a/0x6e
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[ 14.759438] [<ffffffff81625d52>] system_call_fastpath+0x16/0x1b
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Signed-off-by: Richard Weinberger <rw@linutronix.de>
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Link: http://lkml.kernel.org/r/1323696956-11445-1-git-send-email-rw@linutronix.de
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/printk.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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Index: linux-3.2/kernel/printk.c
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===================================================================
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--- linux-3.2.orig/kernel/printk.c
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+++ linux-3.2/kernel/printk.c
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@@ -902,7 +902,7 @@ asmlinkage int vprintk(const char *fmt,
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boot_delay_msec();
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printk_delay();
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- preempt_disable();
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+ migrate_disable();
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/* This stops the holder of console_sem just where we want him */
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raw_local_irq_save(flags);
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this_cpu = smp_processor_id();
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@@ -1033,7 +1033,7 @@ asmlinkage int vprintk(const char *fmt,
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out_restore_irqs:
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raw_local_irq_restore(flags);
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- preempt_enable();
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+ migrate_enable();
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return printed_len;
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}
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EXPORT_SYMBOL(printk);
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