KASAN: slab-out-of-bounds Read in sg_remove_request

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: d63fdf61 Merge 4.4.120 into android-4.4
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=1709e90b800000
kernel config: https://syzkaller.appspot.com/x/.config?x=b36b3c05dfb8e06d
dashboard link: https://syzkaller.appspot.com/bug?extid=9c4326373dadaf37171e
compiler: gcc (GCC) 7.1.1 20170620
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11ac8ed3800000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122d3fcb800000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9c4326...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy
available)
random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy
available)
random: nonblocking pool is initialized
==================================================================
BUG: KASAN: slab-out-of-bounds in list_empty include/linux/list.h:189
[inline]
BUG: KASAN: slab-out-of-bounds in sg_remove_request+0xf9/0x110
drivers/scsi/sg.c:2120
Read of size 8 at addr ffff8801c6a0d140 by task syzkaller368635/3797

CPU: 1 PID: 3797 Comm: syzkaller368635 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
0000000000000000 619bfea6a23b03e8 ffff8800aaa0fab0 ffffffff81d0408d
ffffea00071a8340 ffff8801c6a0d140 0000000000000000 ffff8801c6a0d140
ffff8800bac32338 ffff8800aaa0fae8 ffffffff814fe143 ffff8801c6a0d140
Call Trace:
[<ffffffff81d0408d>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81d0408d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
[<ffffffff814fe143>] print_address_description+0x73/0x260
mm/kasan/report.c:252
[<ffffffff814fe655>] kasan_report_error mm/kasan/report.c:351 [inline]
[<ffffffff814fe655>] kasan_report+0x285/0x370 mm/kasan/report.c:408
[<ffffffff814fe7b4>] __asan_report_load8_noabort+0x14/0x20
mm/kasan/report.c:429
[<ffffffff825b8439>] list_empty include/linux/list.h:189 [inline]
[<ffffffff825b8439>] sg_remove_request+0xf9/0x110 drivers/scsi/sg.c:2120
[<ffffffff825b89b5>] sg_finish_rem_req+0x295/0x340 drivers/scsi/sg.c:1837
[<ffffffff825ba85b>] sg_read+0xa1b/0x1490 drivers/scsi/sg.c:537
[<ffffffff8151cf33>] __vfs_read+0x103/0x440 fs/read_write.c:432
[<ffffffff8151edd3>] vfs_read+0x123/0x3a0 fs/read_write.c:454
[<ffffffff81521719>] SYSC_read fs/read_write.c:569 [inline]
[<ffffffff81521719>] SyS_read+0xd9/0x1b0 fs/read_write.c:562
[<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801c6a0d100
which belongs to the cache fasync_cache of size 96
The buggy address is located 64 bytes inside of
96-byte region [ffff8801c6a0d100, ffff8801c6a0d160)
The buggy address belongs to the page:
Initializing cgroup subsys cpuset
Initializing cgroup subsys cpu
Initializing cgroup subsys cpuacct
Initializing cgroup subsys schedtune
Linux version 4.4.120-gd63fdf6 (syzkaller@ci) (gcc version 7.1.1 20170620
(GCC) ) #28 SMP PREEMPT Tue Mar 6 13:16:06 UTC 2018
Command line: BOOT_IMAGE=/vmlinuz root=/dev/sda1 console=ttyS0
earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu
oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400
workqueue.watchdog_thresh=120
KERNEL supported cpus:
Intel GenuineIntel
AMD AuthenticAMD
Centaur CentaurHauls
x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256
x86/fpu: Supporting XSAVE feature 0x01: 'x87 floating point registers'
x86/fpu: Supporting XSAVE feature 0x02: 'SSE registers'
x86/fpu: Supporting XSAVE feature 0x04: 'AVX registers'
x86/fpu: Enabled xstate features 0x7, context size is 832 bytes,
using 'standard' format.
x86/fpu: Using 'eager' FPU context switches.
e820: BIOS-provided physical RAM map:
BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
BIOS-e820: [mem 0x0000000000100000-0x00000000bfff2fff] usable
BIOS-e820: [mem 0x00000000bfff3000-0x00000000bfffffff] reserved
BIOS-e820: [mem 0x00000000fffbc000-0x00000000ffffffff] reserved
BIOS-e820: [mem 0x0000000100000000-0x000000021fffffff] usable
bootconsole [earlyser0] enabled
NX (Execute Disable) protection: active
SMBIOS 2.4 present.
Hypervisor detected: KVM
e820: last_pfn = 0x220000 max_arch_pfn = 0x400000000
x86/PAT: Configuration [0-7]: WB WC UC- UC WB WC UC- WT
e820: last_pfn = 0xbfff3 max_arch_pfn = 0x400000000
found SMP MP-table at [mem 0x000f23e0-0x000f23ef] mapped at
[ffff8800000f23e0]
Scanning 1 areas for low memory corruption
Using GB pages for direct mapping
ACPI: Early table checksum verification disabled
ACPI: RSDP 0x00000000000F23A0 000014 (v00 Google)
ACPI: RSDT 0x00000000BFFF3430 000038 (v01 Google GOOGRSDT 00000001 GOOG
00000001)
ACPI: FACP 0x00000000BFFFCF60 0000F4 (v02 Google GOOGFACP 00000001 GOOG
00000001)
ACPI: DSDT 0x00000000BFFF3470 0017B2 (v01 Google GOOGDSDT 00000001 GOOG
00000001)
ACPI: FACS 0x00000000BFFFCF00 000040
ACPI: FACS 0x00000000BFFFCF00 000040
ACPI: SSDT 0x00000000BFFF65F0 00690D (v01 Google GOOGSSDT 00000001 GOOG
00000001)
ACPI: APIC 0x00000000BFFF5D10 000076 (v01 Google GOOGAPIC 00000001 GOOG
00000001)
ACPI: WAET 0x00000000BFFF5CE0 000028 (v01 Google GOOGWAET 00000001 GOOG
00000001)
ACPI: SRAT 0x00000000BFFF4C30 0000C8 (v01 Google GOOGSRAT 00000001 GOOG
00000001)
kvm-clock: Using msrs 4b564d01 and 4b564d00
kvm-clock: cpu 0, msr 2:1fffd001, primary cpu clock
kvm-clock: using sched offset of 2579838721 cycles
clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb,
max_idle_ns: 881590591483 ns
Zone ranges:
DMA [mem 0x0000000000001000-0x0000000000ffffff]
DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
Normal [mem 0x0000000100000000-0x000000021fffffff]
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x0000000000001000-0x000000000009efff]
node 0: [mem 0x0000000000100000-0x00000000bfff2fff]
node 0: [mem 0x0000000100000000-0x000000021fffffff]
Initmem setup node 0 [mem 0x0000000000001000-0x000000021fffffff]
kasan: KernelAddressSanitizer initialized
ACPI: PM-Timer IO Port: 0xb008
ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1])
IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23
ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level)
ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level)
Using ACPI (MADT) for SMP configuration information
smpboot: Allowing 2 CPUs, 0 hotplug CPUs
PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff]
PM: Registered nosave memory: [mem 0x000a0000-0x000effff]
PM: Registered nosave memory: [mem 0x000f0000-0x000fffff]
PM: Registered nosave memory: [mem 0xbfff3000-0xbfffffff]
PM: Registered nosave memory: [mem 0xc0000000-0xfffbbfff]
PM: Registered nosave memory: [mem 0xfffbc000-0xffffffff]
e820: [mem 0xc0000000-0xfffbbfff] available for PCI devices
Booting paravirtualized kernel on KVM
clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff,
max_idle_ns: 19112604462750000 ns
setup_percpu: NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:2 nr_node_ids:1
PERCPU: Embedded 42 pages/cpu @ffff8801db200000 s134024 r8192 d29816
u1048576
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1935227
Kernel command line: BOOT_IMAGE=/vmlinuz root=/dev/sda1 console=ttyS0
earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu
oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400
workqueue.watchdog_thresh=120
PID hash table entries: 4096 (order: 3, 32768 bytes)
Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes)
Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes)
Memory: 6581404K/7863876K available (40422K kernel code, 6136K rwdata,
8808K rodata, 1848K init, 23616K bss, 1282472K reserved, 0K cma-reserved)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
Kernel/User page tables isolation: enabled
Running RCU self tests
Preemptible hierarchical RCU implementation.
RCU lockdep checking is enabled.
Build-time adjustment of leaf fanout to 64.
RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=2.
RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=2
NR_IRQS:4352 nr_irqs:440 16
console [ttyS0] enabled
console [ttyS0] enabled
bootconsole [earlyser0] disabled
bootconsole [earlyser0] disabled
Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
... MAX_LOCKDEP_SUBCLASSES: 8
... MAX_LOCK_DEPTH: 48
... MAX_LOCKDEP_KEYS: 8191
... CLASSHASH_SIZE: 4096
... MAX_LOCKDEP_ENTRIES: 32768
... MAX_LOCKDEP_CHAINS: 65536
... CHAINHASH_SIZE: 32768
memory used by lock dependency info: 8159 kB
per task-struct memory footprint: 1920 bytes
tsc: Detected 2300.000 MHz processor
Calibrating delay loop (skipped) preset value.. 4600.00 BogoMIPS
(lpj=23000000)
pid_max: default: 32768 minimum: 301
ACPI: Core revision 20150930
ACPI: 2 ACPI AML tables successfully acquired and loaded
Security Framework initialized
SELinux: Initializing.
AppArmor: AppArmor disabled by boot time parameter
Mount-cache hash table entries: 16384 (order: 5, 131072 bytes)
Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes)
Initializing cgroup subsys io
Initializing cgroup subsys freezer
Initializing cgroup subsys hugetlb
Initializing cgroup subsys debug
CPU: Physical Processor ID: 0
mce: CPU supports 32 MCE banks
Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024
Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4
Spectre V2 : Vulnerable: Minimal generic ASM retpoline
Freeing SMP alternatives memory: 44K
..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1
smpboot: CPU0: Intel(R) Xeon(R) CPU @ 2.30GHz (family: 0x6, model: 0x3f,
stepping: 0x0)
Performance Events: unsupported p6 CPU model 63 no PMU driver, software
events only.
x86: Booting SMP configuration:
.... node #0, CPUs: #1
kvm-clock: cpu 1, msr 2:1fffd041, secondary cpu clock
x86: Booted up 1 node, 2 CPUs
smpboot: Total of 2 processors activated (9200.00 BogoMIPS)
devtmpfs: initialized
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns:
19112604462750000 ns
futex hash table entries: 512 (order: 4, 65536 bytes)
xor: automatically using best checksumming function:
kworker/u4:0 (21) used greatest stack depth: 27944 bytes left
avx : 21463.200 MB/sec
RTC time: 6:51:29, date: 03/25/18
NET: Registered protocol family 16
schedtune: init normalization constants...
schedtune: no energy model data
schedtune: disabled!
cpuidle: using governor ladder
cpuidle: using governor menu
ACPI: bus type PCI registered
acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
PCI: Using configuration type 1 for base access
kworker/u4:2 (47) used greatest stack depth: 27448 bytes left
kworker/u4:2 (484) used greatest stack depth: 27080 bytes left
raid6: sse2x1 gen() 4763 MB/s
raid6: sse2x1 xor() 2638 MB/s
raid6: sse2x2 gen() 7543 MB/s
raid6: sse2x2 xor() 4351 MB/s
raid6: sse2x4 gen() 9833 MB/s
raid6: sse2x4 xor() 5646 MB/s
raid6: avx2x1 gen() 9405 MB/s
raid6: avx2x2 gen() 12351 MB/s
raid6: avx2x4 gen() 18220 MB/s
raid6: using algorithm avx2x4 gen() 18220 MB/s
raid6: using avx2x2 recovery algorithm
ACPI: Added _OSI(Module Device)
ACPI: Added _OSI(Processor Device)
ACPI: Added _OSI(3.0 _SCP Extensions)
ACPI: Added _OSI(Processor Aggregator Device)
ACPI: Executed 2 blocks of module-level executable AML code
ACPI: Interpreter enabled
ACPI: (supports S0 S3 S4 S5)
ACPI: Using IOAPIC for interrupt routing
PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and
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