Messages in this thread | | | Date | Tue, 3 Feb 2015 14:14:37 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm/swapfile.c: use spin_lock_bh with swap_lock to avoid deadlocks |
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On Mon 02-02-15 18:25:28, pasi.sjoholm@jolla.com wrote: > From: Pasi Sjöholm <pasi.sjoholm@jollamobile.com> > > It is possible to get kernel in deadlock-state if swap_lock is not locked > with spin_lock_bh by calling si_swapinfo() simultaneously through > timer_function and registered vm shinker callback-function. > > BUG: spinlock recursion on CPU#0, main/2447 > lock: swap_lock+0x0/0x10, .magic: dead4ead, .owner: main/2447, .owner_cpu: 0 > [<c010b938>] (unwind_backtrace+0x0/0x11c) from [<c03e9be0>] (do_raw_spin_lock+0x48/0x154) > [<c03e9be0>] (do_raw_spin_lock+0x48/0x154) from [<c0226e10>] (si_swapinfo+0x10/0x90) > [<c0226e10>] (si_swapinfo+0x10/0x90) from [<c04d7e18>] (timer_function+0x24/0x258)
Who is calling si_swapinfo from timer_function? AFAICS the vanilla kernel doesn't do that. Or am I missing something? -- Michal Hocko SUSE Labs
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