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BUG: KASAN: slab-out-of-bounds in qrtr_endpoint_post+0x1182/0x11c0 net/qrtr/qrtr.c:511
Read of size 4 at addr ffff888014bc982c by task syz-executor.5/7115

CPU: 0 PID: 7115 Comm: syz-executor.5 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
 qrtr_endpoint_post+0x1182/0x11c0 net/qrtr/qrtr.c:511
 qrtr_tun_write_iter+0x125/0x1a0 net/qrtr/tun.c:108
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write+0x426/0x650 fs/read_write.c:518
 vfs_write+0x75a/0xa40 fs/read_write.c:605
 ksys_write+0x12d/0x250 fs/read_write.c:658
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1ea6dca188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9
RDX: 0000000000000020 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 0000000000a9fb1f R14: 00007f1ea6dca300 R15: 0000000000022000

Allocated by task 7115:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:596 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 qrtr_tun_write_iter+0xbf/0x1a0 net/qrtr/tun.c:99
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write+0x426/0x650 fs/read_write.c:518
 vfs_write+0x75a/0xa40 fs/read_write.c:605
 ksys_write+0x12d/0x250 fs/read_write.c:658
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888014bc9800
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 12 bytes to the right of
 32-byte region [ffff888014bc9800, ffff888014bc9820)
The buggy address belongs to the page:
page:ffffea000052f240 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14bc9
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000ca0d80 0000000200000002 ffff888010841500
raw: 0000000000000000 0000000080400040 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 2740910070, free_ts 2738305477
 prep_new_page mm/page_alloc.c:2436 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2119
 alloc_pages+0x238/0x2a0 mm/mempolicy.c:2242
 alloc_slab_page mm/slub.c:1688 [inline]
 allocate_slab+0x32e/0x4b0 mm/slub.c:1828
 new_slab mm/slub.c:1891 [inline]
 new_slab_objects mm/slub.c:2637 [inline]
 ___slab_alloc+0x4ba/0x820 mm/slub.c:2800
 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2840
 slab_alloc_node mm/slub.c:2922 [inline]
 slab_alloc mm/slub.c:2964 [inline]
 __kmalloc_track_caller+0x2fe/0x320 mm/slub.c:4617
 __do_krealloc mm/slab_common.c:1206 [inline]
 krealloc+0x87/0xf0 mm/slab_common.c:1239
 add_sysfs_param+0x152/0x960 kernel/params.c:642
 kernel_add_sysfs_param kernel/params.c:794 [inline]
 param_sysfs_builtin kernel/params.c:833 [inline]
 param_sysfs_init+0x359/0x498 kernel/params.c:952
 do_one_initcall+0x103/0x650 init/main.c:1282
 do_initcall_level init/main.c:1355 [inline]
 do_initcalls init/main.c:1371 [inline]
 do_basic_setup init/main.c:1391 [inline]
 kernel_init_freeable+0x6b8/0x741 init/main.c:1593
 kernel_init+0x1a/0x1d0 init/main.c:1485
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1346 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
 free_unref_page_prepare mm/page_alloc.c:3332 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3411
 mm_free_pgd kernel/fork.c:636 [inline]
 __mmdrop+0xcb/0x3f0 kernel/fork.c:687
 mmdrop include/linux/sched/mm.h:49 [inline]
 __mmput+0x3b4/0x470 kernel/fork.c:1111
 mmput+0x58/0x60 kernel/fork.c:1122
 free_bprm+0x65/0x2e0 fs/exec.c:1479
 kernel_execve+0x380/0x460 fs/exec.c:1976
 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff888014bc9700: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888014bc9780: fb fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff888014bc9800: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
                                  ^
 ffff888014bc9880: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff888014bc9900: fb fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
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