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BUG: KASAN: use-after-free in ax25_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline]
BUG: KASAN: use-after-free in ax25_fillin_cb+0x39c/0x588 net/ax25/af_ax25.c:495
Read of size 4 at addr ffff0000d616d238 by task syz.0.183/4862

CPU: 0 PID: 4862 Comm: syz.0.183 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 __asan_report_load4_noabort+0x44/0x50 mm/kasan/report_generic.c:308
 ax25_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline]
 ax25_fillin_cb+0x39c/0x588 net/ax25/af_ax25.c:495
 ax25_setsockopt+0x980/0xcdc net/ax25/af_ax25.c:690
 __sys_setsockopt+0x3a8/0x6b4 net/socket.c:2203
 __do_sys_setsockopt net/socket.c:2214 [inline]
 __se_sys_setsockopt net/socket.c:2211 [inline]
 __arm64_sys_setsockopt+0xb8/0xd4 net/socket.c:2211
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Allocated by task 4197:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc+0x29c/0x4c8 mm/slub.c:4407
 kmalloc_array include/linux/slab.h:631 [inline]
 kcalloc include/linux/slab.h:660 [inline]
 ext4_find_extent+0x288/0xbdc fs/ext4/extents.c:907
 ext4_ext_map_blocks+0x2bc/0x6418 fs/ext4/extents.c:4165
 ext4_map_blocks+0x8d0/0x1a44 fs/ext4/inode.c:672
 mpage_map_one_extent fs/ext4/inode.c:2407 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2460 [inline]
 ext4_writepages+0x12c0/0x36fc fs/ext4/inode.c:2828
 do_writepages+0x39c/0x5ec mm/page-writeback.c:2386
 __writeback_single_inode+0x148/0x13a4 fs/fs-writeback.c:1647
 writeback_sb_inodes+0x94c/0x1654 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x110/0x39c fs/fs-writeback.c:2001
 wb_writeback+0x410/0xfc8 fs/fs-writeback.c:2106
 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
 wb_do_writeback fs/fs-writeback.c:2259 [inline]
 wb_workfn+0xbb4/0x1070 fs/fs-writeback.c:2288
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
 worker_thread+0x910/0x1034 kernel/workqueue.c:2457
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

Freed by task 4197:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0x178/0x410 mm/slub.c:4559
 ext4_ext_map_blocks+0x3200/0x6418 fs/ext4/extents.c:4433
 ext4_map_blocks+0x8d0/0x1a44 fs/ext4/inode.c:672
 mpage_map_one_extent fs/ext4/inode.c:2407 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2460 [inline]
 ext4_writepages+0x12c0/0x36fc fs/ext4/inode.c:2828
 do_writepages+0x39c/0x5ec mm/page-writeback.c:2386
 __writeback_single_inode+0x148/0x13a4 fs/fs-writeback.c:1647
 writeback_sb_inodes+0x94c/0x1654 fs/fs-writeback.c:1930
 __writeback_inodes_wb+0x110/0x39c fs/fs-writeback.c:2001
 wb_writeback+0x410/0xfc8 fs/fs-writeback.c:2106
 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
 wb_do_writeback fs/fs-writeback.c:2259 [inline]
 wb_workfn+0xbb4/0x1070 fs/fs-writeback.c:2288
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
 worker_thread+0x910/0x1034 kernel/workqueue.c:2457
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

The buggy address belongs to the object at ffff0000d616d200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 56 bytes inside of
 256-byte region [ffff0000d616d200, ffff0000d616d300)
The buggy address belongs to the page:
page:000000000d815eb0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11616c
head:000000000d815eb0 order:1 compound_mapcount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc000341e900 0000000400000003 ffff0000c0002480
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d616d100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d616d180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d616d200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff0000d616d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d616d300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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