================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:264 [inline] BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:307 [inline] BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:325 [inline] BUG: KASAN: slab-use-after-free in p9_fid_put include/net/9p/client.h:275 [inline] BUG: KASAN: slab-use-after-free in v9fs_free_request+0x7d/0x110 fs/9p/vfs_addr.c:128 Write of size 4 at addr ffff888026991f8c by task kworker/u32:3/62 CPU: 2 PID: 62 Comm: kworker/u32:3 Not tainted 6.9.0-rc4-syzkaller-00031-g96fca68c4fbf #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Workqueue: events_unbound v9fs_upload_to_server_worker Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_sub_and_test include/linux/refcount.h:264 [inline] __refcount_dec_and_test include/linux/refcount.h:307 [inline] refcount_dec_and_test include/linux/refcount.h:325 [inline] p9_fid_put include/net/9p/client.h:275 [inline] v9fs_free_request+0x7d/0x110 fs/9p/vfs_addr.c:128 netfs_free_request+0x22f/0x6b0 fs/netfs/objects.c:97 netfs_put_request+0x19b/0x1f0 fs/netfs/objects.c:130 netfs_free_subrequest fs/netfs/objects.c:178 [inline] netfs_put_subrequest+0x408/0x6c0 fs/netfs/objects.c:192 v9fs_upload_to_server fs/9p/vfs_addr.c:36 [inline] v9fs_upload_to_server_worker+0x18c/0x3b0 fs/9p/vfs_addr.c:44 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 8522: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc include/linux/slab.h:628 [inline] kzalloc include/linux/slab.h:749 [inline] p9_fid_create+0x45/0x470 net/9p/client.c:853 p9_client_walk+0xc7/0x550 net/9p/client.c:1154 clone_fid fs/9p/fid.h:23 [inline] v9fs_fid_clone fs/9p/fid.h:33 [inline] v9fs_file_open+0x633/0xba0 fs/9p/vfs_file.c:56 do_dentry_open+0x8da/0x18c0 fs/open.c:955 do_open fs/namei.c:3642 [inline] path_openat+0x1dfb/0x2990 fs/namei.c:3799 do_filp_open+0x1dc/0x430 fs/namei.c:3826 do_sys_openat2+0x17a/0x1e0 fs/open.c:1406 do_sys_open fs/open.c:1421 [inline] __do_sys_creat fs/open.c:1497 [inline] __se_sys_creat fs/open.c:1491 [inline] __ia32_sys_creat+0xcc/0x120 fs/open.c:1491 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 5209: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x390 mm/slub.c:4390 p9_client_destroy+0x14c/0x480 net/9p/client.c:1070 v9fs_session_close+0x49/0x2d0 fs/9p/v9fs.c:506 v9fs_kill_super+0x4d/0xa0 fs/9p/vfs_super.c:196 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472 deactivate_super+0xde/0x100 fs/super.c:505 cleanup_mnt+0x222/0x450 fs/namespace.c:1267 task_work_run+0x14e/0x250 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x82/0x120 arch/x86/entry/common.c:324 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff888026991f80 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 12 bytes inside of freed 96-byte region [ffff888026991f80, ffff888026991fe0) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26991 ksm flags: 0xfff80000000800(slab|node=0|zone=1|lastcpupid=0xfff) page_type: 0xffffffff() raw: 00fff80000000800 ffff888014c42780 ffffea000077ec80 dead000000000003 raw: 0000000000000000 0000000000200020 00000001ffffffff 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 0x12c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (init), ts 17747084907, free_ts 17500351980 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534 prep_new_page mm/page_alloc.c:1541 [inline] get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2175 [inline] allocate_slab mm/slub.c:2338 [inline] new_slab+0xcc/0x3a0 mm/slub.c:2391 ___slab_alloc+0x670/0x16d0 mm/slub.c:3525 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610 __slab_alloc_node mm/slub.c:3663 [inline] slab_alloc_node mm/slub.c:3835 [inline] __do_kmalloc_node mm/slub.c:3965 [inline] __kmalloc+0x3b4/0x440 mm/slub.c:3979 kmalloc_array include/linux/slab.h:665 [inline] kcalloc include/linux/slab.h:696 [inline] ext4_find_extent+0x95c/0xce0 fs/ext4/extents.c:914 ext4_ext_map_blocks+0x27d/0x5ce0 fs/ext4/extents.c:4143 ext4_map_blocks+0x848/0x17d0 fs/ext4/inode.c:551 ext4_mpage_readpages+0xfef/0x1a10 fs/ext4/readpage.c:290 ext4_readahead+0x102/0x140 fs/ext4/inode.c:3143 read_pages+0x1a8/0xda0 mm/readahead.c:160 page_cache_ra_unbounded+0x450/0x5a0 mm/readahead.c:269 do_page_cache_ra mm/readahead.c:299 [inline] page_cache_ra_order+0x64b/0x9a0 mm/readahead.c:539 ondemand_readahead+0x520/0x1140 mm/readahead.c:661 page last free pid 61 tgid 61 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1141 [inline] free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487 vfree+0x181/0x7a0 mm/vmalloc.c:3340 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3261 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Memory state around the buggy address: ffff888026991e80: 00 00 00 00 00 00 00 00 00 00 00 06 fc fc fc fc ffff888026991f00: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc >ffff888026991f80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888026992000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888026992080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================