Messages in this thread Patch in this message | | | Date | Thu, 26 Jan 2006 17:29:22 +0100 | From | Ingo Molnar <> | Subject | [patch] drivers/block/floppy.c: dont free_irq() from irq context |
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free_irq() should not be executed from softirq context.
Found by the lock validator:
============================ [ BUG: illegal lock usage! ] ---------------------------- illegal {enabled-softirqs} -> {used-in-softirq} usage. rcu_torture_rea/265 [HC0[0]:SC1[2]:HE1:SE0] takes: {proc_subdir_lock} [<c0198163>] remove_proc_entry+0x33/0x1f0 {enabled-softirqs} state was registered at: [<c0122c09>] irq_exit+0x39/0x50 hardirqs last enabled at: [<c04da025>] _spin_unlock_irqrestore+0x25/0x30 softirqs last enabled at: [<c0122c09>] irq_exit+0x39/0x50 other info that might help us debug this: locks held by rcu_torture_rea/265: stack backtrace: [<c010432d>] show_trace+0xd/0x10 [<c0104347>] dump_stack+0x17/0x20 [<c01380f4>] print_usage_bug+0x1c4/0x1e0 [<c0138971>] mark_lock+0x221/0x2c0 [<c0138cc2>] debug_lock_chain+0x2b2/0xd40 [<c013978d>] debug_lock_chain_spin+0x3d/0x60 [<c0266a1d>] _raw_spin_lock+0x2d/0x90 [<c04d9e88>] _spin_lock+0x8/0x10 [<c0198163>] remove_proc_entry+0x33/0x1f0 [<c0142ca9>] unregister_handler_proc+0x19/0x20 [<c014246b>] free_irq+0x7b/0xe0 [<c02f3632>] floppy_release_irq_and_dma+0x1b2/0x210 [<c02f1b27>] set_dor+0xc7/0x1b0 [<c02f4ba1>] motor_off_callback+0x21/0x30 [<c0127605>] run_timer_softirq+0xf5/0x1f0 [<c0122f57>] __do_softirq+0x97/0x130 [<c0105519>] do_softirq+0x69/0x100 =======================
the fix is to push fd_free_irq() into keventd. The code validates fine with this patch applied.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Index: linux/drivers/block/floppy.c =================================================================== --- linux.orig/drivers/block/floppy.c +++ linux/drivers/block/floppy.c @@ -251,6 +251,18 @@ static int irqdma_allocated; #include <linux/cdrom.h> /* for the compatibility eject ioctl */ #include <linux/completion.h> +/* + * Interrupt freeing also means /proc VFS work - dont do it + * from interrupt context. We push this work into keventd: + */ +static void fd_free_irq_fn(void *data) +{ + fd_free_irq(); +} + +static DECLARE_WORK(fd_free_irq_work, fd_free_irq_fn, NULL); + + static struct request *current_req; static struct request_queue *floppy_queue; static void do_fd_request(request_queue_t * q); @@ -4434,6 +4446,13 @@ static int floppy_grab_irq_and_dma(void) return 0; } spin_unlock_irqrestore(&floppy_usage_lock, flags); + + /* + * We might have scheduled a free_irq(), wait it to + * drain first: + */ + flush_scheduled_work(); + if (fd_request_irq()) { DPRINT("Unable to grab IRQ%d for the floppy driver\n", FLOPPY_IRQ); @@ -4523,7 +4542,7 @@ static void floppy_release_irq_and_dma(v if (irqdma_allocated) { fd_disable_dma(); fd_free_dma(); - fd_free_irq(); + schedule_work(&fd_free_irq_work); irqdma_allocated = 0; } set_dor(0, ~0, 8); - 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/
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