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BUG: KASAN: out-of-bounds in csd_lock_record+0xd2/0xe0 kernel/smp.c:119
Read of size 8 at addr ffffc900082c7978 by task syz-executor.3/23575

CPU: 1 PID: 23575 Comm: syz-executor.3 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 csd_lock_record+0xd2/0xe0 kernel/smp.c:119
 flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391
 __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_call_function_single+0xe0/0x120 arch/x86/kernel/smp.c:243
 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:check_preemption_disabled+0xa/0x130 lib/smp_processor_id.c:13
Code: 31 ff 89 de 0f 1f 44 00 00 85 db 75 ae 0f 1f 44 00 00 41 bc 01 00 00 00 e8 13 b2 ac fb eb 9f cc 41 56 41 55 49 89 f5 41 54 55 <48> 89 fd 53 0f 1f 44 00 00 65 44 8b 25 a5 9c 17 78 65 8b 1d be 07
RSP: 0018:ffffc90007d67a48 EFLAGS: 00000282
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffffffff1303b29
RDX: 0000000000000001 RSI: ffffffff8893c000 RDI: ffffffff8893c040
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8aaf028f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff8893c000 R14: 0000000000001000 R15: ffff88808790fdd8
 rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1140 [inline]
 rcu_lockdep_current_cpu_online+0x31/0x110 kernel/rcu/tree.c:1131
 rcu_read_lock_held_common kernel/rcu/update.c:110 [inline]
 rcu_read_lock_held_common kernel/rcu/update.c:100 [inline]
 rcu_read_lock_sched_held+0x25/0xb0 kernel/rcu/update.c:121
 trace_block_touch_buffer include/trace/events/block.h:45 [inline]
 touch_buffer fs/buffer.c:62 [inline]
 __find_get_block+0xb88/0xec0 fs/buffer.c:1370
 sb_find_get_block include/linux/buffer_head.h:338 [inline]
 recently_deleted fs/ext4/ialloc.c:682 [inline]
 find_inode_bit+0x224/0x570 fs/ext4/ialloc.c:724
 __ext4_new_inode+0xc83/0x5390 fs/ext4/ialloc.c:927
 ext4_symlink+0x4b0/0xe10 fs/ext4/namei.c:3303
 vfs_symlink fs/namei.c:3959 [inline]
 vfs_symlink+0x453/0x6a0 fs/namei.c:3945
 do_symlinkat+0x258/0x2c0 fs/namei.c:3986
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c8b7
Code: Bad RIP value.
RSP: 002b:00007ffd3ef6cd48 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045c8b7
RDX: 00007ffd3ef6cde3 RSI: 00000000004c26a1 RDI: 00007ffd3ef6cdd0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013
R10: 0000000000000075 R11: 0000000000000206 R12: 0000000000000001
R13: 00007ffd3ef6cd80 R14: 0000000000000000 R15: 00007ffd3ef6cd90


Memory state around the buggy address:
 ffffc900082c7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900082c7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900082c7900: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
                                                                ^
 ffffc900082c7980: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900082c7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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