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BUG: KASAN: out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc90004d17830 by task syz-executor.0/31663

CPU: 1 PID: 31663 Comm: syz-executor.0 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+0xcb/0xe0 kernel/smp.c:118
 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:__sanitizer_cov_trace_pc+0x49/0x60 kernel/kcov.c:203
Code: 35 8b 82 0c 14 00 00 85 c0 74 2b 8b 82 e8 13 00 00 83 f8 02 75 20 48 8b 8a f0 13 00 00 8b 92 ec 13 00 00 48 8b 01 48 83 c0 01 <48> 39 c2 76 07 48 89 34 c1 48 89 01 c3 66 2e 0f 1f 84 00 00 00 00
RSP: 0018:ffffc9001879e8f8 EFLAGS: 00000216
RAX: 0000000000040000 RBX: ffff888044dac4f8 RCX: ffffc90001bc9000
RDX: 0000000000040000 RSI: ffffffff82047c02 RDI: ffff8880682e4f84
RBP: ffff8880682e4f00 R08: 0000000000000000 R09: ffff888044dac317
R10: 0000000000000087 R11: 0000000000000000 R12: 000000005f0620f4
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc9001879ea18
 ext4_do_update_inode fs/ext4/inode.c:5003 [inline]
 ext4_mark_iloc_dirty+0x7e2/0x3700 fs/ext4/inode.c:5624
 __ext4_mark_inode_dirty+0x237/0x910 fs/ext4/inode.c:5818
 ext4_dirty_inode+0xf3/0x130 fs/ext4/inode.c:5854
 __mark_inode_dirty+0x8cc/0x1300 fs/fs-writeback.c:2260
 mark_inode_dirty_sync include/linux/fs.h:2173 [inline]
 dquot_claim_block include/linux/quotaops.h:367 [inline]
 ext4_da_update_reserve_space+0x5a8/0x7c0 fs/ext4/inode.c:369
 ext4_ext_map_blocks+0x166e/0x61b0 fs/ext4/extents.c:4297
 ext4_map_blocks+0x7b8/0x1650 fs/ext4/inode.c:626
 mpage_map_one_extent fs/ext4/inode.c:2377 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2430 [inline]
 ext4_writepages+0x1c70/0x3960 fs/ext4/inode.c:2782
 do_writepages+0xec/0x290 mm/page-writeback.c:2352
 __filemap_fdatawrite_range+0x2a1/0x380 mm/filemap.c:422
 file_write_and_wait_range+0x169/0x200 mm/filemap.c:761
 ext4_sync_file+0x459/0x1090 fs/ext4/fsync.c:151
 vfs_fsync_range+0x13a/0x220 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2746 [inline]
 ext4_buffered_write_iter+0x34a/0x4a0 fs/ext4/file.c:277
 ext4_file_write_iter+0x1f3/0x13d0 fs/ext4/file.c:655
 call_write_iter include/linux/fs.h:1877 [inline]
 do_iter_readv_writev+0x567/0x780 fs/read_write.c:694
 do_iter_write+0x188/0x5f0 fs/read_write.c:999
 vfs_iter_write+0x70/0xa0 fs/read_write.c:1040
 iter_file_splice_write+0x721/0xbe0 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x171/0x2f0 fs/splice.c:1016
 splice_direct_to_actor+0x38c/0x980 fs/splice.c:971
 do_splice_direct+0x1b3/0x280 fs/splice.c:1059
 do_sendfile+0x559/0xc30 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1576 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x149/0x210 fs/read_write.c:1568
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007f56ad140c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000004fd720 RCX: 000000000045cb29
RDX: 0000000020000480 RSI: 0000000000000007 RDI: 0000000000000007
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000a198 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000902 R14: 00000000004cbe0a R15: 00007f56ad1416d4


Memory state around the buggy address:
 ffffc90004d17700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004d17780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004d17800: f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3 00 00 00 00
                                        ^
 ffffc90004d17880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004d17900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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