6.18-stable review patch. If anyone has any objections, please let me know.
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From: Bhanu Seshu Kumar Valluri bhanuseshukumar@gmail.com
[ Upstream commit 25423cda145f9ed6ee4a72d9f2603ac2a4685e74 ]
When Root Complex (RC) triggers a Doorbell interrupt to Endpoint (EP), it triggers the below warning in the EP:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:271 Call trace: __might_resched+0x130/0x158 __might_sleep+0x70/0x88 mutex_lock+0x2c/0x80 pci_epc_get_msi+0x78/0xd8 pci_epf_test_raise_irq.isra.0+0x74/0x138 pci_epf_test_doorbell_handler+0x34/0x50
The BUG arises because the EP's pci_epf_test_doorbell_handler() which is running in the hard IRQ context is making an indirect call to pci_epc_get_msi(), which uses mutex inside.
To fix the issue, convert the hard IRQ handler to a threaded IRQ handler to allow it to call functions that can sleep during bottom half execution. Also, register the threaded IRQ handler with IRQF_ONESHOT to keep the interrupt line disabled until the threaded IRQ handler completes execution.
Fixes: eff0c286aa91 ("PCI: endpoint: pci-epf-test: Add doorbell test support") Signed-off-by: Bhanu Seshu Kumar Valluri bhanuseshukumar@gmail.com [mani: reworded description a bit] Signed-off-by: Manivannan Sadhasivam mani@kernel.org Reviewed-by: Niklas Cassel cassel@kernel.org Reviewed-by: Frank Li Frank.Li@nxp.com Link: https://patch.msgid.link/20251014024109.42287-1-bhanuseshukumar@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/endpoint/functions/pci-epf-test.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index 31617772ad516..b05e8db575c35 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -730,8 +730,9 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test, if (bar < BAR_0) goto err_doorbell_cleanup;
- ret = request_irq(epf->db_msg[0].virq, pci_epf_test_doorbell_handler, 0, - "pci-ep-test-doorbell", epf_test); + ret = request_threaded_irq(epf->db_msg[0].virq, NULL, + pci_epf_test_doorbell_handler, IRQF_ONESHOT, + "pci-ep-test-doorbell", epf_test); if (ret) { dev_err(&epf->dev, "Failed to request doorbell IRQ: %d\n",