[tip: perf/core] perf/x86/intel/uncore: Fix reference count leak in __uncore_imc_init_box()

[tip-bot2 for Xiongfeng Wang]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     17b8d847b92d815d1638f0de154654081d66b281
Gitweb:        https://git.kernel.org/tip/17b8d847b92d815d1638f0de154654081d66b281
Author:        Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
AuthorDate:    Fri, 18 Nov 2022 14:31:37 +08:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 24 Nov 2022 11:09:26 +01:00

perf/x86/intel/uncore: Fix reference count leak in __uncore_imc_init_box()

pci_get_device() will increase the reference count for the returned
pci_dev, so tgl_uncore_get_mc_dev() will return a pci_dev with its
reference count increased. We need to call pci_dev_put() to decrease the
reference count before exiting from __uncore_imc_init_box(). Add
pci_dev_put() for both normal and error path.

Fixes: fdb64822443e ("perf/x86: Add Intel Tiger Lake uncore support")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221118063137.121512-5-wangxiongfeng2@xxxxxxxxxx
---
 arch/x86/events/intel/uncore_snb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c
index 1ef4f78..1f48692 100644
--- a/arch/x86/events/intel/uncore_snb.c
+++ b/arch/x86/events/intel/uncore_snb.c
@@ -1338,6 +1338,7 @@ static void __uncore_imc_init_box(struct intel_uncore_box *box,
 	/* MCHBAR is disabled */
 	if (!(mch_bar & BIT(0))) {
 		pr_warn("perf uncore: MCHBAR is disabled. Failed to map IMC free-running counters.\n");
+		pci_dev_put(pdev);
 		return;
 	}
 	mch_bar &= ~BIT(0);
@@ -1352,6 +1353,8 @@ static void __uncore_imc_init_box(struct intel_uncore_box *box,
 	box->io_addr = ioremap(addr, type->mmio_map_size);
 	if (!box->io_addr)
 		pr_warn("perf uncore: Failed to ioremap for %s.\n", type->name);
+
+	pci_dev_put(pdev);
 }
 
 static void tgl_uncore_imc_freerunning_init_box(struct intel_uncore_box *box)