KASAN: slab-out-of-bounds Read in riscv_intc_irq (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0966d385830d riscv: Fix auipc+jalr relocation range checks
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
console output: https://syzkaller.appspot.com/x/log.txt?x=117b55ba880000
kernel config: https://syzkaller.appspot.com/x/.config?x=6295d67591064921
dashboard link: https://syzkaller.appspot.com/bug?extid=70d5d5d83d03db2c813d
compiler: riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: riscv64
CC: [a...@eecs.berkeley.edu linux-...@vger.kernel.org linux...@lists.infradead.org m...@kernel.org pal...@dabbelt.com paul.w...@sifive.com tg...@linutronix.de]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+70d5d5...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in riscv_intc_irq+0x24/0xc8 drivers/irqchip/irq-riscv-intc.c:24
Read of size 8 at addr ffffaf802076ff30 by task syz-executor.0/2039

CPU: 0 PID: 2039 Comm: syz-executor.0 Not tainted 5.17.0-rc1-syzkaller-00002-g0966d385830d #0
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
[<ffffffff8000a228>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:113
[<ffffffff831668cc>] show_stack+0x34/0x40 arch/riscv/kernel/stacktrace.c:119
[<ffffffff831756ba>] __dump_stack lib/dump_stack.c:88 [inline]
[<ffffffff831756ba>] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:106
[<ffffffff8047479e>] print_address_description.constprop.0+0x2a/0x330 mm/kasan/report.c:255
[<ffffffff80474d4c>] __kasan_report mm/kasan/report.c:442 [inline]
[<ffffffff80474d4c>] kasan_report+0x184/0x1e0 mm/kasan/report.c:459
[<ffffffff80475b20>] check_region_inline mm/kasan/generic.c:183 [inline]
[<ffffffff80475b20>] __asan_load8+0x6e/0x96 mm/kasan/generic.c:256
[<ffffffff80c43cf8>] riscv_intc_irq+0x24/0xc8 drivers/irqchip/irq-riscv-intc.c:24
[<ffffffff831a1a1a>] generic_handle_arch_irq+0x36/0x54 kernel/irq/handle.c:238
[<ffffffff80005724>] ret_from_exception+0x0/0x10
[<ffffffff80009fd6>] walk_stackframe+0xa0/0x260 arch/riscv/kernel/stacktrace.c:46

Allocated by task 0:
(stack is not available)

Last potentially related work creation:
stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0x80/0xb2 mm/kasan/common.c:524
kasan_kmalloc include/linux/kasan.h:270 [inline]
__kmalloc+0x190/0x318 mm/slub.c:4424
kmalloc include/linux/slab.h:586 [inline]
kzalloc include/linux/slab.h:715 [inline]
kobject_get_path+0xac/0x16e lib/kobject.c:179
kobject_uevent_env+0x1de/0xdfe lib/kobject_uevent.c:529
kobject_uevent+0x22/0x2e lib/kobject_uevent.c:642
kset_register+0xf8/0x114 lib/kobject.c:881
bus_register+0x17e/0x6de drivers/base/bus.c:804
subsys_register drivers/base/bus.c:1083 [inline]
subsys_virtual_register+0x34/0x7a drivers/base/bus.c:1163
wq_sysfs_init+0x24/0x6c kernel/workqueue.c:5701
do_one_initcall+0x13a/0x7ea init/main.c:1300
do_initcall_level init/main.c:1373 [inline]
do_initcalls init/main.c:1389 [inline]
do_basic_setup init/main.c:1408 [inline]
kernel_init_freeable+0x510/0x5b4 init/main.c:1613
kernel_init+0x28/0x21c init/main.c:1502
ret_from_exception+0x0/0x10

Second to last potentially related work creation:
stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
__kasan_slab_alloc+0x8e/0x98 mm/kasan/common.c:469
kasan_slab_alloc include/linux/kasan.h:260 [inline]
early_kmem_cache_node_alloc mm/slub.c:3945 [inline]
init_kmem_cache_nodes mm/slub.c:3986 [inline]
kmem_cache_open mm/slub.c:4232 [inline]
__kmem_cache_create+0x34c/0x688 mm/slub.c:4893
create_boot_cache+0x72/0x9c mm/slab_common.c:649
kmem_cache_init+0xe4/0x1ba mm/slub.c:4827
mm_init+0x10a/0x138 init/main.c:840
start_kernel+0x20e/0x698 init/main.c:985

The buggy address belongs to the object at ffffaf802076fe80
which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 8 bytes to the right of
168-byte region [ffffaf802076fe80, ffffaf802076ff28)
The buggy address belongs to the page:
page:ffffaf807af6a738 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa096f
flags: 0xa000000200(slab|section=20|node=0|zone=0)
raw: 000000a000000200 0000000000000000 0000000000000122 ffffaf80072ed280
raw: 0000000000000000 0000000000110011 00000001ffffffff 0000000000000000
raw: 00000000000007ff
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 2039, ts 623901312500, free_ts 623820495300
__set_page_owner+0x48/0x136 mm/page_owner.c:183
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0xd0/0x10a mm/page_alloc.c:2427
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0x8da/0x12d8 mm/page_alloc.c:4165
__alloc_pages+0x150/0x3b6 mm/page_alloc.c:5389
alloc_pages+0x132/0x2a6 mm/mempolicy.c:2271
alloc_slab_page.constprop.0+0xc2/0xfa mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x76/0x2cc mm/slub.c:2004
___slab_alloc+0x56e/0x918 mm/slub.c:3018
__slab_alloc.constprop.0+0x50/0x8c mm/slub.c:3105
slab_alloc_node mm/slub.c:3196 [inline]
slab_alloc mm/slub.c:3238 [inline]
kmem_cache_alloc+0x39c/0x3de mm/slub.c:3243
kmem_cache_zalloc include/linux/slab.h:705 [inline]
__kernfs_new_node+0xfc/0x5f2 fs/kernfs/dir.c:585
kernfs_new_node+0x66/0xbe fs/kernfs/dir.c:647
__kernfs_create_file+0x4e/0x1e8 fs/kernfs/file.c:987
sysfs_add_file_mode_ns+0x138/0x254 fs/sysfs/file.c:294
sysfs_create_file_ns+0x100/0x15a fs/sysfs/file.c:355
sysfs_create_file include/linux/sysfs.h:607 [inline]
device_create_file+0x9c/0x130 drivers/base/core.c:2760
page last free stack trace:
__reset_page_owner+0x4a/0xea mm/page_owner.c:142
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1352 [inline]
free_pcp_prepare+0x29c/0x45e mm/page_alloc.c:1404
free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page_list+0x148/0x7fe mm/page_alloc.c:3441
release_pages+0x3f0/0xad0 mm/swap.c:980
free_pages_and_swap_cache+0x74/0x86 mm/swap_state.c:320
tlb_batch_pages_flush mm/mmu_gather.c:50 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:243 [inline]
tlb_flush_mmu mm/mmu_gather.c:250 [inline]
tlb_finish_mmu+0xe8/0x29a mm/mmu_gather.c:341
exit_mmap+0x170/0x412 mm/mmap.c:3180
__mmput kernel/fork.c:1114 [inline]
mmput+0xee/0x2c2 kernel/fork.c:1135
free_bprm+0xbc/0x1de fs/exec.c:1485
kernel_execve+0x214/0x288 fs/exec.c:1982
call_usermodehelper_exec_async+0x1c0/0x2dc kernel/umh.c:112
ret_from_exception+0x0/0x10

Memory state around the buggy address:
ffffaf802076fe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffaf802076fe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffaf802076ff00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
^
ffffaf802076ff80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
ffffaf8020770000: f1 f1 f1 f1 00 00 00 f3 f3 f3 f3 f3 00 00 00 00
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.