[PATCH AUTOSEL for 4.4 096/101] iommu/vt-d: clean up pr_irq if request_threaded_irq fails

Sasha Levin
2018-03-08T05:23:16Z

From: Jerry Snitselaar <jsnitsel@redhat.com>

[ Upstream commit 72d548113881dd32bf7f0b221d031e6586468437 ]

It is unlikely request_threaded_irq will fail, but if it does for some
reason we should clear iommu->pr_irq in the error path. Also
intel_svm_finish_prq shouldn't try to clean up the page request
interrupt if pr_irq is 0. Without these, if request_threaded_irq were
to fail the following occurs:

fail with no fixes:

[ 0.683147] ------------[ cut here ]------------
[ 0.683148] NULL pointer, cannot free irq
[ 0.683158] WARNING: CPU: 1 PID: 1 at kernel/irq/irqdomain.c:1632 irq_domain_free_irqs+0x126/0x140
[ 0.683160] Modules linked in:
[ 0.683163] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2 #3
[ 0.683165] Hardware name: /NUC7i3BNB, BIOS BNKBL357.86A.0036.2017.0105.1112 01/05/2017
[ 0.683168] RIP: 0010:irq_domain_free_irqs+0x126/0x140
[ 0.683169] RSP: 0000:ffffc90000037ce8 EFLAGS: 00010292
[ 0.683171] RAX: 000000000000001d RBX: ffff880276283c00 RCX: ffffffff81c5e5e8
[ 0.683172] RDX: 0000000000000001 RSI: 0000000000000096 RDI: 0000000000000246
[ 0.683174] RBP: ffff880276283c00 R08: 0000000000000000 R09: 000000000000023c
[ 0.683175] R10: 0000000000000007 R11: 0000000000000000 R12: 000000000000007a
[ 0.683176] R13: 0000000000000001 R14: 0000000000000000 R15: 0000010010000000
[ 0.683178] FS: 0000000000000000(0000) GS:ffff88027ec80000(0000) knlGS:0000000000000000
[ 0.683180] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.683181] CR2: 0000000000000000 CR3: 0000000001c09001 CR4: 00000000003606e0
[ 0.683182] Call Trace:
[ 0.683189] intel_svm_finish_prq+0x3c/0x60
[ 0.683191] free_dmar_iommu+0x1ac/0x1b0
[ 0.683195] init_dmars+0xaaa/0xaea
[ 0.683200] ? klist_next+0x19/0xc0
[ 0.683203] ? pci_do_find_bus+0x50/0x50
[ 0.683205] ? pci_get_dev_by_id+0x52/0x70
[ 0.683208] intel_iommu_init+0x498/0x5c7
[ 0.683211] pci_iommu_init+0x13/0x3c
[ 0.683214] ? e820__memblock_setup+0x61/0x61
[ 0.683217] do_one_initcall+0x4d/0x1a0
[ 0.683220] kernel_init_freeable+0x186/0x20e
[ 0.683222] ? set_debug_rodata+0x11/0x11
[ 0.683225] ? rest_init+0xb0/0xb0
[ 0.683226] kernel_init+0xa/0xff
[ 0.683229] ret_from_fork+0x1f/0x30
[ 0.683259] Code: 89 ee 44 89 e7 e8 3b e8 ff ff 5b 5d 44 89 e7 44 89 ee 41 5c 41 5d 41 5e e9 a8 84 ff ff 48 c7 c7 a8 71 a7 81 31 c0 e8 6a d3 f9 ff <0f> ff 5b 5d 41 5c 41 5d 41 5
e c3 0f 1f 44 00 00 66 2e 0f 1f 84
[ 0.683285] ---[ end trace f7650e42792627ca ]---

with iommu->pr_irq = 0, but no check in intel_svm_finish_prq:

[ 0.669561] ------------[ cut here ]------------
[ 0.669563] Trying to free already-free IRQ 0
[ 0.669573] WARNING: CPU: 3 PID: 1 at kernel/irq/manage.c:1546 __free_irq+0xa4/0x2c0
[ 0.669574] Modules linked in:
[ 0.669577] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2 #4
[ 0.669579] Hardware name: /NUC7i3BNB, BIOS BNKBL357.86A.0036.2017.0105.1112 01/05/2017
[ 0.669581] RIP: 0010:__free_irq+0xa4/0x2c0
[ 0.669582] RSP: 0000:ffffc90000037cc0 EFLAGS: 00010082
[ 0.669584] RAX: 0000000000000021 RBX: 0000000000000000 RCX: ffffffff81c5e5e8
[ 0.669585] RDX: 0000000000000001 RSI: 0000000000000086 RDI: 0000000000000046
[ 0.669587] RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000023c
[ 0.669588] R10: 0000000000000007 R11: 0000000000000000 R12: ffff880276253960
[ 0.669589] R13: ffff8802762538a4 R14: ffff880276253800 R15: ffff880276283600
[ 0.669593] FS: 0000000000000000(0000) GS:ffff88027ed80000(0000) knlGS:0000000000000000
[ 0.669594] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.669596] CR2: 0000000000000000 CR3: 0000000001c09001 CR4: 00000000003606e0
[ 0.669602] Call Trace:
[ 0.669616] free_irq+0x30/0x60
[ 0.669620] intel_svm_finish_prq+0x34/0x60
[ 0.669623] free_dmar_iommu+0x1ac/0x1b0
[ 0.669627] init_dmars+0xaaa/0xaea
[ 0.669631] ? klist_next+0x19/0xc0
[ 0.669634] ? pci_do_find_bus+0x50/0x50
[ 0.669637] ? pci_get_dev_by_id+0x52/0x70
[ 0.669639] intel_iommu_init+0x498/0x5c7
[ 0.669642] pci_iommu_init+0x13/0x3c
[ 0.669645] ? e820__memblock_setup+0x61/0x61
[ 0.669648] do_one_initcall+0x4d/0x1a0
[ 0.669651] kernel_init_freeable+0x186/0x20e
[ 0.669653] ? set_debug_rodata+0x11/0x11
[ 0.669656] ? rest_init+0xb0/0xb0
[ 0.669658] kernel_init+0xa/0xff
[ 0.669661] ret_from_fork+0x1f/0x30
[ 0.669662] Code: 7a 08 75 0e e9 c3 01 00 00 4c 39 7b 08 74 57 48 89 da 48 8b 5a 18 48 85 db 75 ee 89 ee 48 c7 c7 78 67 a7 81 31 c0 e8 4c 37 fa ff <0f> ff 48 8b 34 24 4c 89 ef e
8 0e 4c 68 00 49 8b 46 40 48 8b 80
[ 0.669688] ---[ end trace 58a470248700f2fc ]---

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/iommu/intel-svm.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index f929879ecae6..a7d516f973dd 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -127,6 +127,7 @@ int intel_svm_enable_prq(struct intel_iommu *iommu)
pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
iommu->name);
dmar_free_hwirq(irq);
+ iommu->pr_irq = 0;
goto err;
}
dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
@@ -142,9 +143,11 @@ int intel_svm_finish_prq(struct intel_iommu *iommu)
dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);

- free_irq(iommu->pr_irq, iommu);
- dmar_free_hwirq(iommu->pr_irq);
- iommu->pr_irq = 0;
+ if (iommu->pr_irq) {
+ free_irq(iommu->pr_irq, iommu);
+ dmar_free_hwirq(iommu->pr_irq);
+ iommu->pr_irq = 0;
+ }

free_pages((unsigned long)iommu->prq, PRQ_ORDER);
iommu->prq = NULL;
--
2.14.1