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padata: add separate cpuhp node for CPUHP_PADATA_DEAD
Removing the pcrypt module triggers this: general protection fault, probably for non-canonical address 0xdead000000000122 CPU: 5 PID: 264 Comm: modprobe Not tainted 5.6.0+ STMicroelectronics#2 Hardware name: QEMU Standard PC RIP: 0010:__cpuhp_state_remove_instance+0xcc/0x120 Call Trace: padata_sysfs_release+0x74/0xce kobject_put+0x81/0xd0 padata_free+0x12/0x20 pcrypt_exit+0x43/0x8ee [pcrypt] padata instances wrongly use the same hlist node for the online and dead states, so __padata_free()'s second cpuhp remove call chokes on the node that the first poisoned. cpuhp multi-instance callbacks only walk forward in cpuhp_step->list and the same node is linked in both the online and dead lists, so the list corruption that results from padata_alloc() adding the node to a second list without removing it from the first doesn't cause problems as long as no instances are freed. Avoid the issue by giving each state its own node. Fixes: 894c9ef ("padata: validate cpumask without removed CPU during offline") Signed-off-by: Daniel Jordan <[email protected]> Cc: Herbert Xu <[email protected]> Cc: Steffen Klassert <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] # v5.4+ Signed-off-by: Herbert Xu <[email protected]>
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