Messages in this thread | | | From | Tvrtko Ursulin <> | Subject | Shift overflow in qi_flush_dev_iotlb | Date | Fri, 20 Oct 2017 19:36:54 +0100 |
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Hi all,
Detected by ubsan:
UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1345:3 shift exponent 64 is too large for 32-bit type 'int' CPU: 2 PID: 1167 Comm: perf_pmu Not tainted 4.14.0-rc5+ #532 Hardware name: LENOVO 80MX/Lenovo E31-80, BIOS DCCN34WW(V2.03) 12/01/2015 Call Trace: <IRQ> dump_stack+0xab/0xfe ? _atomic_dec_and_lock+0x112/0x112 ? get_unsigned_val+0x48/0x91 ubsan_epilogue+0x9/0x49 __ubsan_handle_shift_out_of_bounds+0x1ea/0x241 ? __ubsan_handle_load_invalid_value+0x136/0x136 ? _raw_spin_unlock_irqrestore+0x32/0x50 ? qi_submit_sync+0x642/0x820 ? qi_flush_dev_iotlb+0x158/0x1b0 qi_flush_dev_iotlb+0x158/0x1b0 ? qi_flush_iotlb+0x110/0x110 ? do_raw_spin_lock+0x93/0x130 iommu_flush_dev_iotlb+0xff/0x170 iommu_flush_iova+0x168/0x220 iova_domain_flush+0x2b/0x50 fq_flush_timeout+0xa6/0x1e0 ? fq_ring_free+0x260/0x260 ? call_timer_fn+0xfd/0x600 call_timer_fn+0x160/0x600 ? fq_ring_free+0x260/0x260 ? trace_timer_cancel+0x1d0/0x1d0 ? _raw_spin_unlock_irq+0x29/0x40 ? fq_ring_free+0x260/0x260 ? fq_ring_free+0x260/0x260 run_timer_softirq+0x3bb/0x9a0 ? timer_fixup_init+0x30/0x30 ? __lock_is_held+0x35/0x150 ? sched_clock_cpu+0x14/0x180 __do_softirq+0x159/0x9c7 irq_exit+0x118/0x170 smp_apic_timer_interrupt+0xda/0x530 apic_timer_interrupt+0x9d/0xb0 </IRQ> RIP: 0010:__asan_load4+0xa/0x80 RSP: 0018:ffff88012f647380 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10 RAX: ffff7fffffffffff RBX: ffff88012f647548 RCX: ffffffff9a07ea01 RDX: dffffc0000000000 RSI: ffff88012f647808 RDI: ffff88012f647548 RBP: ffff88012f640000 R08: fffffbfff3b27e96 R09: fffffbfff3b27e95 R10: ffffffff9d93f4ad R11: fffffbfff3b27e96 R12: ffff88012f648000 R13: ffff88012f647558 R14: ffff88012f647550 R15: ffff88012f647808 ? stack_access_ok+0x61/0x110 stack_access_ok+0x6d/0x110 deref_stack_reg+0x64/0x120 ? __read_once_size_nocheck.constprop.3+0x50/0x50 ? deref_stack_reg+0x120/0x120 ? __kmalloc+0x13a/0x550 unwind_next_frame+0xc04/0x14e0 ? kasan_kmalloc+0xa0/0xd0 ? __kmalloc+0x13a/0x550 ? __kmalloc+0x13a/0x550 ? deref_stack_reg+0x120/0x120 ? unwind_next_frame+0xf3e/0x14e0 ? i915_gem_do_execbuffer+0x4fd/0x2570 [i915] __save_stack_trace+0x7a/0x120 ? __kmalloc+0x13a/0x550 save_stack+0x33/0xa0 ? save_stack+0x33/0xa0 ? kasan_kmalloc+0xa0/0xd0 ? _raw_spin_unlock+0x24/0x30 ? deactivate_slab+0x650/0xb90 ? ___slab_alloc+0x3e0/0x940 ? ___slab_alloc+0x3e0/0x940 ? i915_gem_do_execbuffer+0x4fd/0x2570 [i915] ? __lock_is_held+0x35/0x150 ? mark_held_locks+0x33/0x130 ? kasan_unpoison_shadow+0x30/0x40 kasan_kmalloc+0xa0/0xd0 __kmalloc+0x13a/0x550 ? depot_save_stack+0x16a/0x7f0 i915_gem_do_execbuffer+0x4fd/0x2570 [i915] ? save_stack+0x92/0xa0 ? eb_relocate_slow+0x890/0x890 [i915] ? debug_check_no_locks_freed+0x200/0x200 ? ___slab_alloc+0x3e0/0x940 ? ___slab_alloc+0x3e0/0x940 ? i915_gem_execbuffer2+0xdb/0x5f0 [i915] ? __lock_is_held+0x35/0x150 ? i915_gem_execbuffer+0x580/0x580 [i915] i915_gem_execbuffer2+0x2c1/0x5f0 [i915] ? i915_gem_execbuffer+0x580/0x580 [i915] ? lock_downgrade+0x310/0x310 ? i915_gem_execbuffer+0x580/0x580 [i915] drm_ioctl_kernel+0xdc/0x190 drm_ioctl+0x46a/0x6e0 ? i915_gem_execbuffer+0x580/0x580 [i915] ? drm_setversion+0x430/0x430 ? lock_downgrade+0x310/0x310 do_vfs_ioctl+0x138/0xbf0 ? ioctl_preallocate+0x180/0x180 ? do_raw_spin_unlock+0xf5/0x1d0 ? do_raw_spin_trylock+0x90/0x90 ? task_work_run+0x35/0x120 ? mark_held_locks+0x33/0x130 ? _raw_spin_unlock_irq+0x29/0x40 ? mark_held_locks+0x33/0x130 ? entry_SYSCALL_64_fastpath+0x5/0xad ? trace_hardirqs_on_caller+0x184/0x360 SyS_ioctl+0x3b/0x70 entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x7fc0e1f0d587 RSP: 002b:00007ffcfd9929f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007fc0e1f0d587 RDX: 00007ffcfd992a90 RSI: 0000000040406469 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007ffcfd992a50 R09: 0000000000000000 R10: 0000000000000073 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code is:
void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep, u64 addr, unsigned mask) { struct qi_desc desc;
if (mask) { BUG_ON(addr & ((1 << (VTD_PAGE_SHIFT + mask)) - 1));
^^^ This last line is where the warning comes. Digging deeper VTD_PAGE_SHIFT is 12 and the passed in mask comes from iommu_flush_iova (via iommu_flush_dev_iotlb) as MAX_AGAW_PFN_WIDTH which is:
#define MAX_AGAW_WIDTH 64 #define MAX_AGAW_PFN_WIDTH (MAX_AGAW_WIDTH - VTD_PAGE_SHIFT)
So mask is 64, which overflows the left shift in the BUG_ON.
Regards,
Tvrtko
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