[syzbot] [iommu?] KASAN: slab-use-after-free Read in free_iova

[syzbot <syzbot+90c2d711b5218d10ce61@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    562bfb501c54 Merge tag 'integrity-v7.2-rc7' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17ba93b9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c05be6c9b0d36cb9
dashboard link: https://syzkaller.appspot.com/bug?extid=90c2d711b5218d10ce61
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-562bfb50.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7580e6506574/vmlinux-562bfb50.xz
kernel image: https://storage.googleapis.com/syzbot-assets/883f7f234497/bzImage-562bfb50.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+90c2d711b5218d10ce61@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in private_find_iova drivers/iommu/iova.c:285 [inline]
BUG: KASAN: slab-use-after-free in free_iova+0xab/0x200 drivers/iommu/iova.c:355
Read of size 8 at addr ffff888000274d60 by task syz.0.0/5327

CPU: 0 UID: 0 PID: 5327 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <IRQ>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 private_find_iova drivers/iommu/iova.c:285 [inline]
 free_iova+0xab/0x200 drivers/iommu/iova.c:355
 fq_ring_free_locked+0x1ab/0x310 drivers/iommu/dma-iommu.c:155
 fq_ring_free drivers/iommu/dma-iommu.c:170 [inline]
 fq_flush_timeout+0x234/0x2d0 drivers/iommu/dma-iommu.c:194
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline]
RIP: 0010:console_flush_all+0x7d2/0xaf0 kernel/printk/printk.c:3343
Code: ff ff e8 81 3b 21 00 90 0f 0b 90 e9 9c fc ff ff e8 73 3b 21 00 e8 ce 5d 2d 0a 48 85 db 74 c0 e8 64 3b 21 00 fb 48 8b 5c 24 18 <48> 8b 44 24 28 42 80 3c 20 00 4d 8d 77 58 74 08 4c 89 f7 e8 e6 6d
RSP: 0018:ffffc9000f6271e0 EFLAGS: 00000283
RAX: ffffffff81a5e75c RBX: ffffc9000f627340 RCX: 0000000000100000
RDX: ffffc9000edfa000 RSI: 000000000002c5aa RDI: 000000000002c5ab
RBP: ffffc9000f6272f0 R08: ffffffff9057c237 R09: 1ffffffff20af846
R10: dffffc0000000000 R11: fffffbfff20af847 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000000 R15: ffffffff8f471ce0
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
 __warn_printf lib/bug.c:189 [inline]
 __report_bug+0x3c5/0x570 lib/bug.c:249
 report_bug_entry+0x19a/0x290 lib/bug.c:274
 handle_bug+0xce/0x200 arch/x86/kernel/traps.c:431
 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:490
 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:593
RIP: 0010:debug_print_object+0x18a/0x230 lib/debugobjects.c:629
Code: f8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ff e8 3d 13 56 fd 4d 8b 0f 4c 89 ef 48 8b 74 24 08 48 89 ea 44 89 e1 4d 89 f0 ff 34 24 <67> 48 0f b9 3a 48 83 c4 08 ff 05 03 b3 77 0b 48 83 c4 10 5b 41 5c
RSP: 0018:ffffc9000f6276f0 EFLAGS: 00010246
RAX: 1ffffffff17decd0 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffffffff8c4bf940 RSI: ffffffff8c4bf3c0 RDI: ffffffff90632440
RBP: ffffffff8c4bf940 R08: ffff8880002684e0 R09: ffffffff8bef79e0
R10: dffffc0000000000 R11: ffffffff81b33db0 R12: 0000000000000000
R13: ffffffff90632440 R14: ffff8880002684e0 R15: ffffffff8bef6680
 __debug_check_no_obj_freed lib/debugobjects.c:1171 [inline]
 debug_check_no_obj_freed+0x2e3/0x450 lib/debugobjects.c:1201
 slab_free_hook mm/slub.c:2608 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x13e/0x640 mm/slub.c:6692
 iommu_domain_free drivers/iommu/iommu.c:2131 [inline]
 iommu_deinit_device+0x401/0x840 drivers/iommu/iommu.c:600
 __iommu_group_remove_device+0x1dd/0x270 drivers/iommu/iommu.c:764
 iommu_release_device drivers/iommu/iommu.c:783 [inline]
 iommu_bus_notifier+0x6d/0x2c0 drivers/iommu/iommu.c:1826
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 bus_notify+0x143/0x180 drivers/base/bus.c:1086
 device_del+0x740/0x8f0 drivers/base/core.c:3978
 pci_destroy_dev drivers/pci/remove.c:46 [inline]
 pci_remove_bus_device+0x12a/0x2a0 drivers/pci/remove.c:110
 pci_stop_and_remove_bus_device drivers/pci/remove.c:129 [inline]
 pci_stop_and_remove_bus_device_locked+0x7f/0xb0 drivers/pci/remove.c:136
 remove_store+0xe5/0x150 drivers/pci/pci-sysfs.c:523
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2afa79e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2afb6f9fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2afaa25fa0 RCX: 00007f2afa79e019
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000008
RBP: 00007f2afa83500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2afaa26038 R14: 00007f2afaa25fa0 R15: 00007fff4eb947c8
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4931
 alloc_iova_mem drivers/iommu/iova.c:231 [inline]
 alloc_and_init_iova drivers/iommu/iova.c:474 [inline]
 __insert_new_range drivers/iommu/iova.c:489 [inline]
 reserve_iova+0x2b0/0x480 drivers/iommu/iova.c:544
 iova_reserve_pci_windows drivers/iommu/dma-iommu.c:521 [inline]
 iova_reserve_iommu_regions drivers/iommu/dma-iommu.c:563 [inline]
 iommu_dma_init_domain drivers/iommu/dma-iommu.c:723 [inline]
 iommu_setup_dma_ops+0xa21/0x1820 drivers/iommu/dma-iommu.c:2159
 bus_iommu_probe+0x296/0x470 drivers/iommu/iommu.c:1983
 iommu_device_register+0x1af/0x210 drivers/iommu/iommu.c:307
 intel_iommu_init+0x6f0/0x8e0 drivers/iommu/intel/iommu.c:2662
 pci_iommu_init+0x38/0x70 arch/x86/kernel/pci-dma.c:174
 do_one_initcall+0x250/0x870 init/main.c:1347
 do_initcall_level+0x10a/0x1a0 init/main.c:1409
 do_initcalls+0x59/0xa0 init/main.c:1425
 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658
 kernel_init+0x1d/0x1d0 init/main.c:1548
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5327:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x182/0x650 mm/slub.c:6504
 free_iova_mem drivers/iommu/iova.c:237 [inline]
 put_iova_domain+0xcc/0x100 drivers/iommu/iova.c:454
 iommu_put_dma_cookie+0x45c/0x560 drivers/iommu/dma-iommu.c:431
 iommu_domain_free drivers/iommu/iommu.c:2131 [inline]
 iommu_deinit_device+0x401/0x840 drivers/iommu/iommu.c:600
 __iommu_group_remove_device+0x1dd/0x270 drivers/iommu/iommu.c:764
 iommu_release_device drivers/iommu/iommu.c:783 [inline]
 iommu_bus_notifier+0x6d/0x2c0 drivers/iommu/iommu.c:1826
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 bus_notify+0x143/0x180 drivers/base/bus.c:1086
 device_del+0x740/0x8f0 drivers/base/core.c:3978
 pci_destroy_dev drivers/pci/remove.c:46 [inline]
 pci_remove_bus_device+0x12a/0x2a0 drivers/pci/remove.c:110
 pci_stop_and_remove_bus_device drivers/pci/remove.c:129 [inline]
 pci_stop_and_remove_bus_device_locked+0x7f/0xb0 drivers/pci/remove.c:136
 remove_store+0xe5/0x150 drivers/pci/pci-sysfs.c:523
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888000274d40
 which belongs to the cache iommu_iova of size 40
The buggy address is located 32 bytes inside of
 freed 40-byte region [ffff888000274d40, ffff888000274d68)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x274
flags: 0x7ff00000000000(node=0|zone=0|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 007ff00000000000 ffff888030463500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8498569964, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3380
 new_slab mm/slub.c:3426 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 kmem_cache_alloc_noprof+0x382/0x5f0 mm/slub.c:4931
 alloc_iova_mem drivers/iommu/iova.c:231 [inline]
 alloc_and_init_iova drivers/iommu/iova.c:474 [inline]
 __insert_new_range drivers/iommu/iova.c:489 [inline]
 reserve_iova+0x2b0/0x480 drivers/iommu/iova.c:544
 iova_reserve_pci_windows drivers/iommu/dma-iommu.c:521 [inline]
 iova_reserve_iommu_regions drivers/iommu/dma-iommu.c:563 [inline]
 iommu_dma_init_domain drivers/iommu/dma-iommu.c:723 [inline]
 iommu_setup_dma_ops+0xa21/0x1820 drivers/iommu/dma-iommu.c:2159
 bus_iommu_probe+0x296/0x470 drivers/iommu/iommu.c:1983
 iommu_device_register+0x1af/0x210 drivers/iommu/iommu.c:307
 intel_iommu_init+0x6f0/0x8e0 drivers/iommu/intel/iommu.c:2662
 pci_iommu_init+0x38/0x70 arch/x86/kernel/pci-dma.c:174
 do_one_initcall+0x250/0x870 init/main.c:1347
 do_initcall_level+0x10a/0x1a0 init/main.c:1409
 do_initcalls+0x59/0xa0 init/main.c:1425
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888000274c00: 00 00 00 00 00 fc fc fc 00 00 00 00 00 fc fc fc
 ffff888000274c80: fa fb fb fb fb fc fc fc fa fb fb fb fb fc fc fc
>ffff888000274d00: fa fb fb fb fb fc fc fc fa fb fb fb fb fc fc fc
                                                       ^
 ffff888000274d80: fa fb fb fb fb fc fc fc 00 00 00 00 00 fc fc fc
 ffff888000274e00: 00 00 00 00 00 fc fc fc 00 00 00 00 00 fc fc fc
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	ff                   	ljmp   (bad)
   1:	e8 81 3b 21 00       	call   0x213b87
   6:	90                   	nop
   7:	0f 0b                	ud2
   9:	90                   	nop
   a:	e9 9c fc ff ff       	jmp    0xfffffcab
   f:	e8 73 3b 21 00       	call   0x213b87
  14:	e8 ce 5d 2d 0a       	call   0xa2d5de7
  19:	48 85 db             	test   %rbx,%rbx
  1c:	74 c0                	je     0xffffffde
  1e:	e8 64 3b 21 00       	call   0x213b87
  23:	fb                   	sti
  24:	48 8b 5c 24 18       	mov    0x18(%rsp),%rbx
* 29:	48 8b 44 24 28       	mov    0x28(%rsp),%rax <-- trapping instruction
  2e:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
  33:	4d 8d 77 58          	lea    0x58(%r15),%r14
  37:	74 08                	je     0x41
  39:	4c 89 f7             	mov    %r14,%rdi
  3c:	e8                   	.byte 0xe8
  3d:	e6 6d                	out    %al,$0x6d


---
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