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Date: Mon, 09 Jan 2012 18:05:32 +0100 From: Miklos Szeredi <miklos@...redi.hu> To: Linus Torvalds <torvalds@...ux-foundation.org> Cc: viro@...iv.linux.org.uk, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, mgorman@...e.de, gregkh@...e.de, hch@...radead.org, akpm@...ux-foundation.org Subject: Re: [RFC PATCH] shrink_dcache_parent() deadlock Linus Torvalds <torvalds@...ux-foundation.org> writes: > On Mon, Jan 9, 2012 at 2:58 AM, Miklos Szeredi <miklos@...redi.hu> wrote: >> >> This patch adds a new dentry flag that is set when the dentry is removed >> from the lru and put on the list being processed by >> shrink_dentry_list(). The flag is cleared in dentry_lru_del() which is >> called if the dentry gets a new reference just before it's pruned. >> >> Thoughts? > > Looks reasonable. Were you actually able to reproduce the hang, or how > did you notice? We got a bug report from a partner about hang during reboot. It's actually quite easily reproducible with: while true; do echo -bond0 > /sys/class/net/bonding_masters echo +bond0 > /sys/class/net/bonding_masters echo -bond1 > /sys/class/net/bonding_masters echo +bond1 > /sys/class/net/bonding_masters done That reliably triggers the soft lookup detector for several machines that we tested. It's rather timing sensitive though, because turning on DEBUG_SPINLOCK makes it go away. I had to add printks to see what's going on, because it wasn't obvious from the stack traces and crash dumps. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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