syzbot

 sign-in | mailing list | source | docs
🐞 Open [560] 🐞 Fixed [32] 🐞 Invalid [300] ⬇ Missing Backports [45] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

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

Status: upstream: reported C repro on 2023/06/17 08:07
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+fe3822f23612dee891a2@syzkaller.appspotmail.com
First crash: 320d, last: 229d
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2023/09/15 linux-5.15.y (ToT) aff03380bda4 C [report] KASAN: slab-out-of-bounds Read in read_descriptors
2023/06/17 upstream (ToT) 1639fae5132b C [report] KASAN: slab-out-of-bounds Read in read_descriptors
2023/09/15 upstream (ToT) 9fdfb15a3dbf C Didn't crash
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: slab-out-of-bounds Read in read_descriptors origin:upstream C error 1 275d 320d 0/3 auto-obsoleted due to no activity on 2023/11/08 10:43
upstream KASAN: slab-out-of-bounds Read in read_descriptors (2) usb 1 1350d 1346d 15/26 fixed on 2020/10/10 01:52
upstream KASAN: slab-out-of-bounds Read in read_descriptors usb 1 1655d 1653d 0/26 auto-closed as invalid on 2020/02/18 03:02
upstream KASAN: slab-out-of-bounds Read in read_descriptors (3) usb C error 7 290d 317d 23/26 fixed on 2023/10/12 12:48
upstream KMSAN: uninit-value in read_descriptors (2) usb 1 417d 417d 0/26 auto-obsoleted due to no activity on 2023/06/10 07:49
upstream KMSAN: uninit-value in read_descriptors usb 1 786d 786d 0/26 auto-closed as invalid on 2022/06/06 09:45
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2024/03/22 16:41 0m fix candidate upstream error job log (0)
2024/02/09 13:19 1m fix candidate upstream error job log (0)
2024/01/07 02:01 0m fix candidate upstream error job log (0)
2023/11/30 10:20 0m fix candidate upstream error job log (0)
2023/10/06 18:42 0m fix candidate upstream error job log (0)

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in read_descriptors+0x23c/0x290 drivers/usb/core/sysfs.c:883
Read of size 2 at addr ffff0000ca3ab2aa by task udevd/3963

CPU: 1 PID: 3963 Comm: udevd Not tainted 5.15.117-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 __asan_report_load2_noabort+0x44/0x50 mm/kasan/report_generic.c:307
 read_descriptors+0x23c/0x290 drivers/usb/core/sysfs.c:883
 sysfs_kf_bin_read+0x19c/0x1d4 fs/sysfs/file.c:100
 kernfs_file_read_iter fs/kernfs/file.c:213 [inline]
 kernfs_fop_read_iter+0x32c/0x50c fs/kernfs/file.c:242
 call_read_iter include/linux/fs.h:2097 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x86c/0xb10 fs/read_write.c:485
 ksys_read+0x15c/0x26c fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:631
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Allocated by task 1528:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc+0x29c/0x4c8 mm/slub.c:4407
 kmalloc include/linux/slab.h:596 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 usb_get_configuration+0xd8/0x4048 drivers/usb/core/config.c:882
 usb_enumerate_device drivers/usb/core/hub.c:2400 [inline]
 usb_new_device+0x12c/0x1448 drivers/usb/core/hub.c:2538
 hub_port_connect drivers/usb/core/hub.c:5358 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5502 [inline]
 port_event drivers/usb/core/hub.c:5648 [inline]
 hub_event+0x22e4/0x48c4 drivers/usb/core/hub.c:5730
 process_one_work+0x790/0x11b8 kernel/workqueue.c:2307
 worker_thread+0x910/0x1034 kernel/workqueue.c:2454
 kthread+0x37c/0x45c kernel/kthread.c:319
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

The buggy address belongs to the object at ffff0000ca3ab000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 682 bytes inside of
 1024-byte region [ffff0000ca3ab000, ffff0000ca3ab400)
The buggy address belongs to the page:
page:00000000e42d6beb refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10a3a8
head:00000000e42d6beb order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000122 ffff0000c0002780
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ca3ab180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000ca3ab200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000ca3ab280: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff0000ca3ab300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000ca3ab380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000010f9c4000
[0000000000000000] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 3963 Comm: udevd Tainted: G    B             5.15.117-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
pstate: a0400005 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __memcpy+0x110/0x260 arch/arm64/lib/memcpy.S:158
lr : memcpy+0xc8/0xe8 mm/kasan/shadow.c:69
sp : ffff800018e27900
x29: ffff800018e27900 x28: dfff800000000000 x27: 0000000000000fdc
x26: 0000000000000020 x25: ffff0000d8e59610 x24: 000000000000525a
x23: ffff800016ee1000 x22: ffff80000d7216a4 x21: ffff0000ca1ce024
x20: 0000000000000000 x19: 0000000000000fdc x18: 1fffe0003690338e
x17: 1fffe0003690338e x16: ffff800011952524 x15: ffff80001498f100
x14: ffff0000ca1ce024 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: ffff600019439e00 x9 : 0000000000000000
x8 : 0000000000000001 x7 : 0000000000000000 x6 : ffff800008268c6c
x5 : ffff0000ca1cf000 x4 : 0000000000000fdc x3 : ffff80000d7216a4
x2 : 0000000000000fdc x1 : 0000000000000000 x0 : ffff0000ca1ce024
Call trace:
 __memcpy+0x110/0x260 arch/arm64/lib/memcpy.S:154
 read_descriptors+0x1bc/0x290 drivers/usb/core/sysfs.c:888
 sysfs_kf_bin_read+0x19c/0x1d4 fs/sysfs/file.c:100
 kernfs_file_read_iter fs/kernfs/file.c:213 [inline]
 kernfs_fop_read_iter+0x32c/0x50c fs/kernfs/file.c:242
 call_read_iter include/linux/fs.h:2097 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x86c/0xb10 fs/read_write.c:485
 ksys_read+0x15c/0x26c fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:631
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: cb01000e b4fffc2e eb0201df 540004a3 (a940342c) 
---[ end trace b85945dc2a7bcdb7 ]---
----------------
Code disassembly (best guess):
   0:	cb01000e 	sub	x14, x0, x1
   4:	b4fffc2e 	cbz	x14, 0xffffffffffffff88
   8:	eb0201df 	cmp	x14, x2
   c:	540004a3 	b.cc	0xa0  // b.lo, b.ul, b.last
* 10:	a940342c 	ldp	x12, x13, [x1] <-- trapping instruction

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/17 08:07 linux-5.15.y 471e639e59d1 f3921d4d .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in read_descriptors
2023/07/23 06:03 linux-5.15.y d54cfc420586 27cbe77f .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in read_descriptors
* Struck through repros no longer work on HEAD.