From 504eebffb656a7f95b50128e907638915e7f6dad Mon Sep 17 00:00:00 2001 From: Vishal Chourasia Date: Tue, 15 Oct 2024 16:25:52 +0530 Subject: [PATCH] crypto: nx - Fix invalid wait context during kexec reboot nx842_remove() call of_reconfig_notifier_unregister while holding the devdata_spinlock. This could lead to an invalid wait context error during kexec reboot, as of_reconfig_notifier_unregister tries to acquire a read-write semaphore (check logs) while holding a spinlock. Move the of_reconfig_notifier_unregister() call before acquiring the spinlock to prevent this race condition invalid wait contexts during system shutdown or kexec operations. Log: [ BUG: Invalid wait context ] 6.11.0-test2-10547-g684a64bf32b6-dirty #79 Not tainted ----------------------------- kexec/61926 is trying to lock: c000000002d8b590 ((of_reconfig_chain).rwsem){++++}-{4:4}, at: blocking_notifier_chain_unregister+0x44/0xa0 other info that might help us debug this: context-{5:5} 4 locks held by kexec/61926: #0: c000000002926c70 (system_transition_mutex){+.+.}-{4:4}, at: __do_sys_reboot+0xf8/0x2e0 #1: c00000000291af30 (&dev->mutex){....}-{4:4}, at: device_shutdown+0x160/0x310 #2: c000000051011938 (&dev->mutex){....}-{4:4}, at: device_shutdown+0x174/0x310 #3: c000000002d88070 (devdata_mutex){....}-{3:3}, at: nx842_remove+0xac/0x1bc stack backtrace: CPU: 2 UID: 0 PID: 61926 Comm: kexec Not tainted 6.11.0-test2-10547-g684a64bf32b6-dirty #79 Hardware name: IBM,9080-HEX POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_012) hv:phyp pSeries Call Trace: [c0000000bb577400] [c000000001239704] dump_stack_lvl+0xc8/0x130 (unreliable) [c0000000bb577440] [c000000000248398] __lock_acquire+0xb68/0xf00 [c0000000bb577550] [c000000000248820] lock_acquire.part.0+0xf0/0x2a0 [c0000000bb577670] [c00000000127faa0] down_write+0x70/0x1e0 [c0000000bb5776b0] [c0000000001acea4] blocking_notifier_chain_unregister+0x44/0xa0 [c0000000bb5776e0] [c000000000e2312c] of_reconfig_notifier_unregister+0x2c/0x40 [c0000000bb577700] [c000000000ded24c] nx842_remove+0x148/0x1bc [c0000000bb577790] [c00000000011a114] vio_bus_remove+0x54/0xc0 [c0000000bb5777c0] [c000000000c1a44c] device_shutdown+0x20c/0x310 [c0000000bb577850] [c0000000001b0ab4] kernel_restart_prepare+0x54/0x70 [c0000000bb577870] [c000000000308718] kernel_kexec+0xa8/0x110 [c0000000bb5778e0] [c0000000001b1144] __do_sys_reboot+0x214/0x2e0 [c0000000bb577a40] [c000000000032f98] system_call_exception+0x148/0x310 [c0000000bb577e50] [c00000000000cedc] system_call_vectored_common+0x15c/0x2ec Signed-off-by: Herbert Xu --- drivers/crypto/nx/nx-common-pseries.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/crypto/nx/nx-common-pseries.c b/drivers/crypto/nx/nx-common-pseries.c index a0eb900383af75..1660c5cf3641c2 100644 --- a/drivers/crypto/nx/nx-common-pseries.c +++ b/drivers/crypto/nx/nx-common-pseries.c @@ -1122,10 +1122,11 @@ static void nx842_remove(struct vio_dev *viodev) crypto_unregister_alg(&nx842_pseries_alg); + of_reconfig_notifier_unregister(&nx842_of_nb); + spin_lock_irqsave(&devdata_spinlock, flags); old_devdata = rcu_dereference_check(devdata, lockdep_is_held(&devdata_spinlock)); - of_reconfig_notifier_unregister(&nx842_of_nb); RCU_INIT_POINTER(devdata, NULL); spin_unlock_irqrestore(&devdata_spinlock, flags); synchronize_rcu();