4.9-stable review patch. If anyone has any objections, please let me know.
------------------
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/intel-svm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -127,6 +127,7 @@ int intel_svm_enable_prq(struct intel_io 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_io 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;