Going more deep into this: This is the initial pcim_intx_resoure associated resource being added during first (CCP) driver load: [ 40.418933] pcim_intx+0x3a/0x120 [ 40.418936] pci_intx+0x8b/0xa0 [ 40.418939] __pci_enable_msix_range+0x369/0x530 [ 40.418943] pci_enable_msix_range+0x18/0x20 [ 40.418946] sp_pci_probe+0x106/0x310 [ccp] [ 40.418965] ipmi device interface [ 40.418960] ? srso_alias_return_thunk+0x5/0xfbef5 [ 40.418969] local_pci_probe+0x4f/0xb0 [ 40.418973] work_for_cpu_fn+0x1e/0x30 [ 40.418976] process_one_work+0x183/0x350 [ 40.418980] worker_thread+0x2df/0x3f0 [ 40.418982] ? __pfx_worker_thread+0x10/0x10 [ 40.418985] kthread+0xd0/0x100 [ 40.418987] ? __pfx_kthread+0x10/0x10 [ 40.418990] ret_from_fork+0x40/0x60 [ 40.418993] ? __pfx_kthread+0x10/0x10 [ 40.418996] ret_from_fork_asm+0x1a/0x30 [ 40.419001] </TASK> .. .. [ 40.419012] ccp 0000:23:00.1: DEVRES ADD 00000000fbd19618 0xffff8cfaa528d140 pcim_intx_restore (4 bytes) Now, at driver unload: devres_release_all() -> remove_nodes() -> release_nodes() ... remove_nodes() moves normal devres entries to the todo list, as can be seen with the following log: ... [ 218.245241] moving node 00000000fbd19618 0xffff8cfaa528d140 from devres to todo list ... So, now this pcim_intx_resource associated resource is no longer part of dev->devres_head list and has been moved to the todo list. Later, when release_nodes() is invoked, it calls the associated release() callback associated with this devres: ... [ 218.331000] ccp 0000:23:00.1: DEVRES REL 00000000fbd19618 0xffff8cfaa528d140 pcim_intx_restore (4 bytes) ... The call flow for that is: pcim_intx_restore() -> pci_intx() -> pcim_intx() ... Now, pcim_intx() calls get_or_create_intx_devres() which tries to find it's associated devres using devres_find(), but that fails to find the devres, as the devres is no longer on dev->devres_head and has been moved to todo list. Therefore, get_or_create_intx_devres() adds a new devres at driver unload/detach time: ... [ 218.361330] ccp 0000:23:00.1: DEVRES ADD 0000000057f8e767 0xffff8cfa867b7740 pcim_intx_restore (4 bytes) ... But, then this is an issue as pcim_intx() is supposed to restore the original PCI INTx state on driver detach, but it now operating on a newly added devres and not the original devres (added at driver probe) which contains the original PCI INTx state, so it will be restoring an incorrect PCI INTx state ? Additionally, this newly added devres causes driver reload/probe failure as really_probe() now finds resources present before probing. Not sure, if this issue has been observed with other PCI device drivers. Thanks, Ashish
