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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 09:50:42 +07:00
c5a99937a9
There is a potential deadlock scenario when the ks8851 driver is removed. The interrupt handler schedules a workqueue which acquires a mutex that ks8851_net_stop() also acquires before flushing the workqueue. Previously lockdep wouldn't be able to find this problem but now that it has the support we can trigger this lockdep warning by rmmoding the driver after an ifconfig up. Fix the possible deadlock by disabling the interrupts in the chip and then release the lock across the workqueue flushing. The mutex is only there to proect the registers anyway so this should be ok. ======================================================= [ INFO: possible circular locking dependency detected ] 3.0.21-00021-g8b33780-dirty #2911 ------------------------------------------------------- rmmod/125 is trying to acquire lock: ((&ks->irq_work)){+.+...}, at: [<c019e0b8>] flush_work+0x0/0xac but task is already holding lock: (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ks->lock){+.+...}: [<c01b89c8>] __lock_acquire+0x940/0x9f8 [<c01b9058>] lock_acquire+0x10c/0x130 [<c083dbec>] mutex_lock_nested+0x68/0x3dc [<bf00bd48>] ks8851_irq_work+0x24/0x46c [ks8851] [<c019c580>] process_one_work+0x2d8/0x518 [<c019cb98>] worker_thread+0x220/0x3a0 [<c01a2ad4>] kthread+0x88/0x94 [<c0107008>] kernel_thread_exit+0x0/0x8 -> #0 ((&ks->irq_work)){+.+...}: [<c01b7984>] validate_chain+0x914/0x1018 [<c01b89c8>] __lock_acquire+0x940/0x9f8 [<c01b9058>] lock_acquire+0x10c/0x130 [<c019e104>] flush_work+0x4c/0xac [<bf00b858>] ks8851_net_stop+0x6c/0x138 [ks8851] [<c06b209c>] __dev_close_many+0x98/0xcc [<c06b2174>] dev_close_many+0x68/0xd0 [<c06b22ec>] rollback_registered_many+0xcc/0x2b8 [<c06b2554>] rollback_registered+0x28/0x34 [<c06b25b8>] unregister_netdevice_queue+0x58/0x7c [<c06b25f4>] unregister_netdev+0x18/0x20 [<bf00c1f4>] ks8851_remove+0x64/0xb4 [ks8851] [<c049ddf0>] spi_drv_remove+0x18/0x1c [<c0468e98>] __device_release_driver+0x7c/0xbc [<c0468f64>] driver_detach+0x8c/0xb4 [<c0467f00>] bus_remove_driver+0xb8/0xe8 [<c01c1d20>] sys_delete_module+0x1e8/0x27c [<c0105ec0>] ret_fast_syscall+0x0/0x3c other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ks->lock); lock((&ks->irq_work)); lock(&ks->lock); lock((&ks->irq_work)); *** DEADLOCK *** 4 locks held by rmmod/125: #0: (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f44>] driver_detach+0x6c/0xb4 #1: (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f50>] driver_detach+0x78/0xb4 #2: (rtnl_mutex){+.+.+.}, at: [<c06b25e8>] unregister_netdev+0xc/0x20 #3: (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851] Cc: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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