[syzbot] [kernel?] KASAN: slab-out-of-bounds Read in reg_fixed_voltage_probe

[syzbot] [kernel?] KASAN: slab-out-of-bounds Read in reg_fixed_voltage_probe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    21d6ac051080 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=10e23a79580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
dashboard link: https://syzkaller.appspot.com/bug?extid=bfc9e55cf4f98183c636
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=172c0679580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17941a25580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/88380e2ddcb9/disk-21d6ac05.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5dba5c2896b7/vmlinux-21d6ac05.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52ac739e37e0/Image-21d6ac05.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bfc9e55cf4f98183c636@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in reg_fixed_voltage_probe+0x90c/0xb88 drivers/regulator/fixed.c:275
Read of size 4 at addr ffff0000ca01b274 by task syz.0.17/4919

CPU: 0 UID: 0 PID: 4919 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
 reg_fixed_voltage_probe+0x90c/0xb88 drivers/regulator/fixed.c:275
 platform_probe+0x100/0x1a4 drivers/base/platform.c:1439
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x29c/0x800 drivers/base/dd.c:706
 __driver_probe_device+0x1e0/0x350 drivers/base/dd.c:868
 device_driver_attach+0x58/0xac drivers/base/dd.c:1203
 bind_store+0xf4/0x14c drivers/base/bus.c:267
 drv_attr_store+0x80/0xa4 drivers/base/bus.c:125
 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x51c/0xa0c fs/read_write.c:687
 ksys_write+0x12c/0x228 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __arm64_sys_write+0x84/0x98 fs/read_write.c:747
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x434/0x6d4 mm/slub.c:5471
 kmemdup_noprof+0x44/0x8c mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:715 [inline]
 platform_device_add_data+0x38/0xb0 drivers/base/platform.c:685
 dummy_hcd_init+0x49c/0xb9c drivers/usb/gadget/udc/dummy_hcd.c:2859
 do_one_initcall+0x274/0xc38 init/main.c:1347
 do_initcall_level+0x12c/0x1c4 init/main.c:1409
 do_initcalls+0x70/0xd0 init/main.c:1425
 do_basic_setup+0x7c/0x90 init/main.c:1445
 kernel_init_freeable+0x268/0x3a8 init/main.c:1658
 kernel_init+0x24/0x1dc init/main.c:1548
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838

The buggy address belongs to the object at ffff0000ca01b260
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 12 bytes to the right of
 allocated 8-byte region [ffff0000ca01b260, ffff0000ca01b268)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10a01b
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000000 ffff0000c0001500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ca01b100: fa fc fc fc fa fc fc fc fa fc fc fc 00 fc fc fc
 ffff0000ca01b180: fa fc fc fc 05 fc fc fc fa fc fc fc 06 fc fc fc
>ffff0000ca01b200: 00 fc fc fc 00 fc fc fc 00 fc fc fc 00 fc fc fc
                                                             ^
 ffff0000ca01b280: 00 fc fc fc 00 fc fc fc fa fc fc fc 00 fc fc fc
 ffff0000ca01b300: fa fc fc fc fa fc fc fc 00 fc fc fc 00 fc fc fc
==================================================================
Unable to handle kernel paging request at virtual address fbd529d5a0000000
KASAN: maybe wild-memory-access in range [0xdead4ead00000000-0xdead4ead00000007]
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, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0
[fbd529d5a0000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 4919 Comm: syz.0.17 Tainted: G    B               syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : strcmp+0x3c/0xf0 lib/string.c:266
lr : regulator_match+0xc8/0xf4 drivers/regulator/core.c:2105
sp : ffff80009acb7310
x29: ffff80009acb7340 x28: 1fffe00019e3796b x27: dfff800000000000
x26: dfff800000000000 x25: ffff80009acb7380 x24: ffff700013596e70
x23: 0000000000000000 x22: dfff800000000000 x21: ffff800086e41920
x20: ffff800086e41aa0 x19: dead4ead00000000 x18: 00000000ffffffff
x17: 3d3d3d3d3d3d3d3d x16: 3d3d3d3d3d3d3d3d x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000000
x11: 1bd5a9d5a0000000 x10: dfff800000000000 x9 : dead4ead00000000
x8 : ffff800086e41920 x7 : 0000000000000000 x6 : ffff8000868a9850
x5 : 0000000000000000 x4 : 0000000000000008 x3 : ffff800080156118
x2 : 0000000000000000 x1 : dead4ead00000000 x0 : ffff800086e41920
Call trace:
 strcmp+0x3c/0xf0 lib/string.c:266 (P)
 regulator_match+0xc8/0xf4 drivers/regulator/core.c:2105
 class_find_device+0xe4/0x1b0 drivers/base/class.c:470
 regulator_lookup_by_name drivers/regulator/core.c:2112 [inline]
 regulator_dev_lookup+0x29c/0x3fc drivers/regulator/core.c:2181
 regulator_resolve_supply+0x1ec/0xe50 drivers/regulator/core.c:2214
 regulator_register+0x9f4/0x1900 drivers/regulator/core.c:6173
 devm_regulator_register+0x5c/0xcc drivers/regulator/devres.c:476
 reg_fixed_voltage_probe+0x6cc/0xb88 drivers/regulator/fixed.c:327
 platform_probe+0x100/0x1a4 drivers/base/platform.c:1439
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x29c/0x800 drivers/base/dd.c:706
 __driver_probe_device+0x1e0/0x350 drivers/base/dd.c:868
 device_driver_attach+0x58/0xac drivers/base/dd.c:1203
 bind_store+0xf4/0x14c drivers/base/bus.c:267
 drv_attr_store+0x80/0xa4 drivers/base/bus.c:125
 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x51c/0xa0c fs/read_write.c:687
 ksys_write+0x12c/0x228 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __arm64_sys_write+0x84/0x98 fs/read_write.c:747
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Code: 7100017f 7a4b1188 540003aa d343fc2b (38ea696c) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	7100017f 	cmp	w11, #0x0
   4:	7a4b1188 	ccmp	w12, w11, #0x8, ne	// ne = any
   8:	540003aa 	b.ge	0x7c  // b.tcont
   c:	d343fc2b 	lsr	x11, x1, #3
* 10:	38ea696c 	ldrsb	w12, [x11, x10] <-- trapping instruction


---
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