================================================================== BUG: KASAN: slab-use-after-free in __up_read+0x627/0x750 kernel/locking/rwsem.c:1342 Read of size 8 at addr ffff888073cde868 by task syz-executor934/6535 CPU: 1 PID: 6535 Comm: syz-executor934 Not tainted 6.6.0-rc7-syzkaller-00195-g2af9b20dbb39 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc4/0x620 mm/kasan/report.c:475 kasan_report+0xda/0x110 mm/kasan/report.c:588 __up_read+0x627/0x750 kernel/locking/rwsem.c:1342 iommufd_put_object drivers/iommu/iommufd/iommufd_private.h:149 [inline] iommufd_vfio_ioas+0x46c/0x580 drivers/iommu/iommufd/vfio_compat.c:146 iommufd_fops_ioctl+0x347/0x4d0 drivers/iommu/iommufd/main.c:398 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f7d7a6505d9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7d7a5f0218 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000037 RCX: 00007f7d7a6505d9 RDX: 0000000020000080 RSI: 0000000000003b88 RDI: 0000000000000003 RBP: 00007f7d7a6da358 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7d7a6d8100 R13: 00007f7d7a6da350 R14: 00007f7d7a6da35c R15: 00007f7d7a6a7074 Allocated by task 6529: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1026 [inline] __kmalloc+0x60/0x100 mm/slab_common.c:1039 kmalloc include/linux/slab.h:603 [inline] kzalloc include/linux/slab.h:720 [inline] _iommufd_object_alloc+0x26/0x1b0 drivers/iommu/iommufd/main.c:40 iommufd_ioas_alloc drivers/iommu/iommufd/ioas.c:27 [inline] iommufd_ioas_alloc_ioctl+0xaf/0x370 drivers/iommu/iommufd/ioas.c:46 iommufd_fops_ioctl+0x347/0x4d0 drivers/iommu/iommufd/main.c:398 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 6536: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x138/0x190 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:164 [inline] __cache_free mm/slab.c:3370 [inline] __do_kmem_cache_free mm/slab.c:3557 [inline] __kmem_cache_free+0xcc/0x2d0 mm/slab.c:3564 iommufd_destroy+0x11e/0x180 drivers/iommu/iommufd/main.c:216 iommufd_fops_ioctl+0x347/0x4d0 drivers/iommu/iommufd/main.c:398 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888073cde800 which belongs to the cache kmalloc-cg-1k of size 1024 The buggy address is located 104 bytes inside of freed 1024-byte region [ffff888073cde800, ffff888073cdec00) The buggy address belongs to the physical page: page:ffffea0001cf3780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x73cde flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0x2() raw: 00fff00000000800 ffff888012c4d800 ffffea000082b690 ffffea0000712a10 raw: 0000000000000000 ffff888073cde000 0000000100000002 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 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 4488, tgid 4488 (udevd), ts 55677988515, free_ts 55675597837 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536 prep_new_page mm/page_alloc.c:1543 [inline] get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426 __alloc_pages_node include/linux/gfp.h:237 [inline] kmem_getpages mm/slab.c:1356 [inline] cache_grow_begin+0x99/0x3a0 mm/slab.c:2550 cache_alloc_refill+0x294/0x3a0 mm/slab.c:2923 ____cache_alloc mm/slab.c:2999 [inline] ____cache_alloc mm/slab.c:2982 [inline] __do_cache_alloc mm/slab.c:3182 [inline] slab_alloc_node mm/slab.c:3230 [inline] __kmem_cache_alloc_node+0x3c5/0x470 mm/slab.c:3521 __do_kmalloc_node mm/slab_common.c:1025 [inline] __kmalloc+0x4f/0x100 mm/slab_common.c:1039 kmalloc_array include/linux/slab.h:636 [inline] kcalloc include/linux/slab.h:667 [inline] alloc_pipe_info+0x1ed/0x580 fs/pipe.c:808 get_pipe_inode fs/pipe.c:882 [inline] create_pipe_files+0x8f/0x870 fs/pipe.c:914 __do_pipe_flags fs/pipe.c:963 [inline] do_pipe2+0xb0/0x1c0 fs/pipe.c:1014 __do_sys_pipe2 fs/pipe.c:1032 [inline] __se_sys_pipe2 fs/pipe.c:1030 [inline] __x64_sys_pipe2+0x54/0x80 fs/pipe.c:1030 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1136 [inline] free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2405 selinux_genfs_get_sid security/selinux/hooks.c:1341 [inline] inode_doinit_with_dentry+0xac0/0x12c0 security/selinux/hooks.c:1539 selinux_d_instantiate+0x26/0x30 security/selinux/hooks.c:6284 security_d_instantiate+0x54/0xe0 security/security.c:3799 d_splice_alias+0x94/0xdf0 fs/dcache.c:3145 kernfs_iop_lookup+0x283/0x330 fs/kernfs/dir.c:1208 __lookup_slow+0x24d/0x450 fs/namei.c:1694 lookup_slow fs/namei.c:1711 [inline] walk_component+0x349/0x5a0 fs/namei.c:2002 lookup_last fs/namei.c:2459 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2483 filename_lookup+0x1e7/0x5b0 fs/namei.c:2512 vfs_statx+0x160/0x430 fs/stat.c:240 vfs_fstatat+0xb3/0x140 fs/stat.c:295 __do_sys_newfstatat+0x98/0x110 fs/stat.c:459 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff888073cde700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888073cde780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888073cde800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888073cde880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888073cde900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================