[4.9-rc1] UBSAN: Undefined behaviour in fs/read_write.c:92:10

[4.9-rc1] UBSAN: Undefined behaviour in fs/read_write.c:92:10

[CAI Qian]

Not sure if it is important.

[ 1416.162804] ================================================================================
[ 1416.172244] UBSAN: Undefined behaviour in fs/read_write.c:92:10
[ 1416.178851] signed integer overflow:
[ 1416.182837] 7957419012188434030 + 5557116669773879724 cannot be represented in type 'long long int'
[ 1416.192937] CPU: 35 PID: 8415 Comm: trinity-c35 Tainted: G        W       4.9.0-rc1 #32
[ 1416.201874] Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRRFSDP1.86B.0271.R00.1510301446 10/30/2015
[ 1416.213236]  ffff880817c5fc90 ffffffff81d23184 0000000041b58ab3 ffffffff8334713f
[ 1416.221537]  ffffffff81d230c4 ffff880817c5fcb8 ffff880817c5fc68 ffff880817c5fc80
[ 1416.229835]  4d1ed82b154619ac ffff880817c5fa78 dffffc0000000000 0000000049134770
[ 1416.238130] Call Trace:
[ 1416.240867]  [<ffffffff81d23184>] dump_stack+0xc0/0x12c
[ 1416.246699]  [<ffffffff81d230c4>] ? _atomic_dec_and_lock+0xc4/0xc4
[ 1416.253600]  [<ffffffff81e46d55>] ubsan_epilogue+0xd/0x8a
[ 1416.259625]  [<ffffffff81e486f4>] handle_overflow+0x211/0x260
[ 1416.266038]  [<ffffffff81e484e3>] ? __ubsan_handle_negate_overflow+0x1b1/0x1b1
[ 1416.274100]  [<ffffffff818e91e2>] ? __fdget_pos+0xa2/0xf0
[ 1416.280125]  [<ffffffff818e91e2>] ? __fdget_pos+0xa2/0xf0
[ 1416.286154]  [<ffffffff82c6b1f0>] ? mutex_lock_interruptible_nested+0xb40/0xb40
[ 1416.294315]  [<ffffffff814b4607>] ? __audit_syscall_exit+0x637/0x960
[ 1416.301406]  [<ffffffff81e48751>] __ubsan_handle_add_overflow+0xe/0x10
[ 1416.308694]  [<ffffffff8186d8f5>] generic_file_llseek_size+0x245/0x3c0
[ 1416.315980]  [<ffffffff81006260>] ? syscall_slow_exit_work+0x4c0/0x4c0
[ 1416.323265]  [<ffffffff8186dbd1>] generic_file_llseek+0xf1/0x1d0
[ 1416.330046]  [<ffffffffa0d09c9c>] xfs_file_llseek+0x2c/0x30 [xfs]
[ 1416.336848]  [<ffffffff8187192d>] SyS_lseek+0xad/0x130
[ 1416.342582]  [<ffffffff81871880>] ? __vfs_read+0x990/0x990
[ 1416.348703]  [<ffffffff8100924d>] do_syscall_64+0x19d/0x540
[ 1416.354924]  [<ffffffff82c76f24>] entry_SYSCALL64_slow_path+0x25/0x25
[ 1416.362103] ================================================================================

[ 1733.283169] ================================================================================
[ 1733.292595] UBSAN: Undefined behaviour in fs/read_write.c:109:12
[ 1733.299300] signed integer overflow:
[ 1733.303290] 8463800222054987125 + 6560120580878238959 cannot be represented in type 'long long int'
[ 1733.313390] CPU: 69 PID: 8584 Comm: trinity-c204 Tainted: G        W       4.9.0-rc1 #32
[ 1733.322421] Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRRFSDP1.86B.0271.R00.1510301446 10/30/2015
[ 1733.333781]  ffff8807d5737c90 ffffffff81d23184 0000000041b58ab3 ffffffff8334713f
[ 1733.342077]  ffffffff81d230c4 ffff8807d5737cb8 ffff8807d5737c68 ffff8807d5737c80
[ 1733.350420]  5b0a3ae94afa04ef ffff8807d5737a78 dffffc0000000000 00000000172a58fb
[ 1733.358718] Call Trace:
[ 1733.361473]  [<ffffffff81d23184>] dump_stack+0xc0/0x12c
[ 1733.367306]  [<ffffffff81d230c4>] ? _atomic_dec_and_lock+0xc4/0xc4
[ 1733.374207]  [<ffffffff81e46d55>] ubsan_epilogue+0xd/0x8a
[ 1733.380232]  [<ffffffff81e486f4>] handle_overflow+0x211/0x260
[ 1733.386644]  [<ffffffff81e484e3>] ? __ubsan_handle_negate_overflow+0x1b1/0x1b1
[ 1733.394710]  [<ffffffff8131d831>] ? __lock_acquire+0xa21/0x1710
[ 1733.401320]  [<ffffffff818e91e2>] ? __fdget_pos+0xa2/0xf0
[ 1733.407348]  [<ffffffff81dce237>] ? debug_smp_processor_id+0x17/0x20
[ 1733.414439]  [<ffffffff813090bd>] ? get_lock_stats+0x1d/0x120
[ 1733.420855]  [<ffffffff8186d73d>] ? generic_file_llseek_size+0x8d/0x3c0
[ 1733.428242]  [<ffffffff81e48751>] __ubsan_handle_add_overflow+0xe/0x10
[ 1733.435527]  [<ffffffff8186da29>] generic_file_llseek_size+0x379/0x3c0
[ 1733.442814]  [<ffffffff81006260>] ? syscall_slow_exit_work+0x4c0/0x4c0
[ 1733.450092]  [<ffffffff8186dbd1>] generic_file_llseek+0xf1/0x1d0
[ 1733.456861]  [<ffffffffa0d09c9c>] xfs_file_llseek+0x2c/0x30 [xfs]
[ 1733.463663]  [<ffffffff8187192d>] SyS_lseek+0xad/0x130
[ 1733.469398]  [<ffffffff81871880>] ? __vfs_read+0x990/0x990
[ 1733.475528]  [<ffffffff8100924d>] do_syscall_64+0x19d/0x540
[ 1733.481753]  [<ffffffff82c76f24>] entry_SYSCALL64_slow_path+0x25/0x25
[ 1733.488941] ================================================================================