On 03.02.2015 15:14, Michal Hocko wrote: >> 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? Nothing in vanilla kernel, but "memnotify" (https://lkml.org/lkml/2012/1/17/182) together with modified lowmemorykiller (drivers/staging/android/lowmemorykiller.c) which takes in account also the available swap (calling si_swapinfo as well) will cause the deadlock. Memnotify uses timer (with backoff) for checking the memory pressure which can be then used to let the processes itself adjust their memory pressure before getting killed by the modified lowmemorykiller. Br, Pasi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>