From: Bhanu Seshu Kumar Valluri <bhanuseshukumar@gmail.com>
To: "Manivannan Sadhasivam" <mani@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Niklas Cassel" <cassel@kernel.org>,
"Frank Li" <Frank.Li@nxp.com>,
"Damien Le Moal" <dlemoal@kernel.org>,
"Mohamed Khalfella" <khalfella@gmail.com>,
"Christian Bruel" <christian.bruel@foss.st.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
khalid@kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
skhan@linuxfoundation.org, david.hunter.linux@gmail.com,
bhanuseshukumar@gmail.com
Subject: [PATCH v3] PCI: endpoint: pci-epf-test: Fix sleeping function being called from atomic context
Date: Tue, 14 Oct 2025 08:11:09 +0530 [thread overview]
Message-ID: <20251014024109.42287-1-bhanuseshukumar@gmail.com> (raw)
When Root Complex (RC) triggers a Doorbell MSI interrupt to Endpoint (EP)
it triggers a warning in the EP. pci_endpoint kselftest target is
compiled and used to run the Doorbell test in RC.
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() is making
an indirect call to pci_epc_get_msi(), which uses mutex inside, from
interrupt context.
To fix the issue convert hard IRQ handler to a threaded IRQ handler to
allow it to call functions that can sleep during bottom half execution.
Register threaded IRQ handler with IRQF_ONESHOT to keep 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>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
---
Note : The patch is compiled and tested on TI am642 board.
Change log
V2->V3:
Addressed Bjorn Helgass review points in v2
- Rebase to pci/main (v6.18-rc1)
- Add a space before each "("
- Remove the timestamps because they're unnecessary distraction
- Add "()" after function names in commit log
- s/irq/IRQ/
- Rewrap the commit log to fit in 75 columns
- Rewrap the code below to fit in 78 columns because most of the
rest of the file does
Link to V2: https://lore.kernel.org/all/20250930023809.7931-1-bhanuseshukumar@gmail.com/
V1->V2:
Trimmed Call trace to include only essential calls.
Used 12 digit commit ID in fixes tag.
Steps to reproduce the bug are removed from commit log.
Link to V1: https://lore.kernel.org/all/20250917161817.15776-1-bhanuseshukumar@gmail.com/
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 31617772a..b05e8db57 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",
--
2.34.1
next reply other threads:[~2025-10-14 2:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-14 2:41 Bhanu Seshu Kumar Valluri [this message]
2025-10-16 16:50 ` [PATCH v3] PCI: endpoint: pci-epf-test: Fix sleeping function being called from atomic context Frank Li
2025-10-26 15:53 ` Manivannan Sadhasivam
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