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Date:   Wed, 12 Oct 2022 09:49:26 -0600
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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Subject: Re: [GIT PULL] Please pull powerpc/linux.git powerpc-6.1-1 tag
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On Wed, Oct 12, 2022 at 07:18:27AM -0700, Guenter Roeck wrote:
> NIP [c000000000031630] .replay_soft_interrupts+0x60/0x300
> LR [c000000000031964] .arch_local_irq_restore+0x94/0x1c0
> Call Trace:
> [c000000007df3870] [c000000000031964] .arch_local_irq_restore+0x94/0x1c0 (unreliable)
> [c000000007df38f0] [c000000000f8a444] .__schedule+0x664/0xa50
> [c000000007df39d0] [c000000000f8a8b0] .schedule+0x80/0x140
> [c000000007df3a50] [c00000000092f0dc] .try_to_generate_entropy+0x118/0x174
> [c000000007df3b40] [c00000000092e2e4] .urandom_read_iter+0x74/0x140
> [c000000007df3bc0] [c0000000003b0044] .vfs_read+0x284/0x2d0
> [c000000007df3cd0] [c0000000003b0d2c] .ksys_read+0xdc/0x130
> [c000000007df3d80] [c00000000002a88c] .system_call_exception+0x19c/0x330
> [c000000007df3e10] [c00000000000c1d4] system_call_common+0xf4/0x258

Obviously the first couple lines of this concern me a bit. But I think
actually this might just be a catalyst for another bug. You could view
that function as basically just:

    while (something)
    	schedule();

And I guess in the process of calling the scheduler a lot, which toggles
interrupts a lot, something got wedged.

Curious, though, I did try to reproduce this, to no avail. My .config is
https://xn--4db.cc/rBvHWfDZ . What's yours?

Jason