syzbot has found a reproducer for the following issue on: HEAD commit: c84e1efa Merge tag 'asm-generic-fixes-5.10-2' of git://git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1251d759500000 kernel config: https://syzkaller.appspot.com/x/.config?x=cb8d1a3819ba4356 dashboard link: https://syzkaller.appspot.com/bug?extid=12056a09a0311d758e60 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1126cce9500000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1173d2e9500000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+12056a09a0311d758e60@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in radix_tree_next_slot include/linux/radix-tree.h:422 [inline] BUG: KASAN: use-after-free in idr_for_each+0x206/0x220 lib/idr.c:202 Read of size 8 at addr ffff888032eb2c40 by task kworker/u4:4/186 CPU: 1 PID: 186 Comm: kworker/u4:4 Not tainted 5.10.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound io_ring_exit_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 radix_tree_next_slot include/linux/radix-tree.h:422 [inline] idr_for_each+0x206/0x220 lib/idr.c:202 io_destroy_buffers fs/io_uring.c:8275 [inline] io_ring_ctx_free fs/io_uring.c:8298 [inline] io_ring_exit_work+0x3f7/0x7a0 fs/io_uring.c:8375 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Allocated by task 10961: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:526 [inline] slab_alloc_node mm/slub.c:2891 [inline] slab_alloc mm/slub.c:2899 [inline] kmem_cache_alloc+0x122/0x460 mm/slub.c:2904 radix_tree_node_alloc.constprop.0+0x7c/0x350 lib/radix-tree.c:274 idr_get_free+0x4c5/0x940 lib/radix-tree.c:1504 idr_alloc_u32+0x170/0x2d0 lib/idr.c:46 idr_alloc+0xc2/0x130 lib/idr.c:87 io_provide_buffers fs/io_uring.c:4032 [inline] io_issue_sqe+0x2fc4/0x3d10 fs/io_uring.c:6012 __io_queue_sqe+0x132/0xda0 fs/io_uring.c:6232 io_queue_sqe+0x623/0x11f0 fs/io_uring.c:6298 io_submit_sqe fs/io_uring.c:6367 [inline] io_submit_sqes+0x15e1/0x28a0 fs/io_uring.c:6596 __do_sys_io_uring_enter+0xc90/0x1ab0 fs/io_uring.c:8983 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 8546: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x102/0x140 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577 slab_free mm/slub.c:3142 [inline] kmem_cache_free+0x82/0x350 mm/slub.c:3158 rcu_do_batch kernel/rcu/tree.c:2476 [inline] rcu_core+0x5df/0xe80 kernel/rcu/tree.c:2711 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0xc0/0xf0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2953 [inline] call_rcu+0xbb/0x700 kernel/rcu/tree.c:3027 radix_tree_node_free lib/radix-tree.c:308 [inline] delete_node+0x591/0x8c0 lib/radix-tree.c:571 __radix_tree_delete+0x190/0x370 lib/radix-tree.c:1377 radix_tree_delete_item+0xe7/0x230 lib/radix-tree.c:1428 __io_remove_buffers fs/io_uring.c:3930 [inline] __io_remove_buffers fs/io_uring.c:3909 [inline] __io_destroy_buffers+0x161/0x200 fs/io_uring.c:8269 idr_for_each+0x113/0x220 lib/idr.c:208 io_destroy_buffers fs/io_uring.c:8275 [inline] io_ring_ctx_free fs/io_uring.c:8298 [inline] io_ring_exit_work+0x3f7/0x7a0 fs/io_uring.c:8375 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 The buggy address belongs to the object at ffff888032eb2c00 which belongs to the cache radix_tree_node of size 576 The buggy address is located 64 bytes inside of 576-byte region [ffff888032eb2c00, ffff888032eb2e40) The buggy address belongs to the page: page:00000000102f3139 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32eb0 head:00000000102f3139 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff88801004db40 raw: 0000000000000000 0000000000170017 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888032eb2b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888032eb2b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888032eb2c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888032eb2c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888032eb2d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
