Messages in this thread | | | Date | Thu, 22 Mar 2007 15:18:13 +1100 | From | Nick Piggin <> | Subject | Re: [1/6] 2.6.21-rc4: known regressions |
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Linus Torvalds wrote:
> In contrast, the hang reported by Mariusz Kozlowski has a slightly > different feel to it, but there's a tantalizing pattern in there too: > > http://www.ussg.iu.edu/hypermail/linux/kernel/0703.0/1243.html > > Call Trace: > [<c03ec87e>] io_schedule+0x42/0x59 > [<c0184915>] sleep_on_buffer+0x8/0xc > [<c03ed217>] __wait_on_bit+0x47/0x6c > [<c03ed297>] out_of_line_wait_on_bit+0x5b/0x64 > [<c01848a8>] __wait_on_buffer+0x27/0x2d > [<c01b4228>] journal_commit_transaction+0x707/0x127f > [<c01b868b>] kjournald+0xac/0x1ed > [<c0126af5>] kthread+0xa2/0xc9 > [<c010422b>] kernel_thread_helper+0x7/0x1c > > which certainly also looks like an IO never completed (or completed but > never woke anything up). > > It also seems to be related to *buffers*. Maybe the whole bh layer thing > is a fluke, but it's not waiting for normal data, it's very much waiting > for those journal things that all use buffer heads.Which just makes me > worry about those patches by Nick (which did come in through Andrew). I > don't think it's the memorder one (it looks safe and shouldn't matter on > x86 anyway!), but what about the > > fs: fix __block_write_full_page error case buffer submission > > locking change for example? Or that "fs: fix nobh data leak" thing with > its fix? It uses "SetPageUptodate(page);" without waking up anybody who > might wait for it (but the waiters here seem to wait on buffers, so that's > probably not it)..
Nothing sleeps on PageUptodate, so I don't think that could explain it.
The fs: fix __block_write_full_page error case buffer submission patch does change the locking, but I'd be really suprised if that was the problem, because it changes locking to match the regular non-error path submission.
It could be possible that ext3 is doing something weird and expecting the old behaviour if it failed get_block, but that seems pretty weird to do, and would need fixing.
fs: nobh data leak... again hard to see how it could cause an unlock/wakeup to get lost. Is Mariusz using the nobh mount option?
It wouldn't hurt to test with these patches backed out...
> Alternatively, maybe it really is an _io_ problem (and the buffer-head > thing is just a red herring, and it could happen to other IO, it's just > that metadata IO uses buffer heads), and it's the scheduler changes since > 2.6.20..
I see what you mean. Could it be an ext3 or jbd change I wonder?
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