FAILED: patch "[PATCH] PCI: endpoint: pci-epf-vntb: Remove duplicate resource" failed to apply to 6.12-stable tree

gregkh
2026-04-20T13:06:25Z

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 0da63230d3ec1ec5fcc443a2314233e95bfece54
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026042022-dormitory-uncrushed-c526@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0da63230d3ec1ec5fcc443a2314233e95bfece54 Mon Sep 17 00:00:00 2001
From: Koichiro Den <den@valinux.co.jp>
Date: Thu, 26 Feb 2026 17:41:38 +0900
Subject: [PATCH] PCI: endpoint: pci-epf-vntb: Remove duplicate resource
teardown

epf_ntb_epc_destroy() duplicates the teardown that the caller is
supposed to perform later. This leads to an oops when .allow_link fails
or when .drop_link is performed. The following is an example oops of the
former case:

Unable to handle kernel paging request at virtual address dead000000000108
[...]
[dead000000000108] address between user and kernel address ranges
Internal error: Oops: 0000000096000044 [#1] SMP
[...]
Call trace:
pci_epc_remove_epf+0x78/0xe0 (P)
pci_primary_epc_epf_link+0x88/0xa8
configfs_symlink+0x1f4/0x5a0
vfs_symlink+0x134/0x1d8
do_symlinkat+0x88/0x138
__arm64_sys_symlinkat+0x74/0xe0
[...]

Remove the helper, and drop pci_epc_put(). EPC device refcounting is
tied to the configfs EPC group lifetime, and pci_epc_put() in the
.drop_link path is sufficient.

Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260226084142.2226875-2-den@valinux.co.jp

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 148a3b160812..42c870ee3956 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -763,19 +763,6 @@ static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb, int num_mws)
}
}

-/**
- * epf_ntb_epc_destroy() - Cleanup NTB EPC interface
- * @ntb: NTB device that facilitates communication between HOST and VHOST
- *
- * Wrapper for epf_ntb_epc_destroy_interface() to cleanup all the NTB interfaces
- */
-static void epf_ntb_epc_destroy(struct epf_ntb *ntb)
-{
- pci_epc_remove_epf(ntb->epf->epc, ntb->epf, 0);
- pci_epc_put(ntb->epf->epc);
-}
-
-
/**
* epf_ntb_is_bar_used() - Check if a bar is used in the ntb configuration
* @ntb: NTB device that facilitates communication between HOST and VHOST
@@ -1529,7 +1516,7 @@ static int epf_ntb_bind(struct pci_epf *epf)
ret = epf_ntb_init_epc_bar(ntb);
if (ret) {
dev_err(dev, "Failed to create NTB EPC\n");
- goto err_bar_init;
+ return ret;
}

ret = epf_ntb_config_spad_bar_alloc(ntb);
@@ -1569,9 +1556,6 @@ static int epf_ntb_bind(struct pci_epf *epf)
err_bar_alloc:
epf_ntb_config_spad_bar_free(ntb);

-err_bar_init:
- epf_ntb_epc_destroy(ntb);
-
return ret;
}

@@ -1587,7 +1571,6 @@ static void epf_ntb_unbind(struct pci_epf *epf)

epf_ntb_epc_cleanup(ntb);
epf_ntb_config_spad_bar_free(ntb);
- epf_ntb_epc_destroy(ntb);

pci_unregister_driver(&vntb_pci_driver);
}