683d2ac390
syzbot reported a kernel warning below: WARNING: CPU: 0 PID: 4499 at mm/slab_common.c:996 kmalloc_slab+0x56/0x70 mm/slab_common.c:996 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 4499 Comm: syz-executor050 Not tainted 4.17.0-rc3+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 panic+0x22f/0x4de kernel/panic.c:184 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 report_bug+0x252/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 RIP: 0010:kmalloc_slab+0x56/0x70 mm/slab_common.c:996 RSP: 0018:ffff8801d907fc58 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801aeecb280 RCX: ffffffff8185ebd7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ffffffe1 RBP: ffff8801d907fc58 R08: ffff8801adb5e1c0 R09: ffffed0035a84700 R10: ffffed0035a84700 R11: ffff8801ad423803 R12: ffff8801aeecb280 R13: 00000000fffffff4 R14: ffff8801ad891a00 R15: 00000000014200c0 __do_kmalloc mm/slab.c:3713 [inline] __kmalloc+0x25/0x760 mm/slab.c:3727 kmalloc include/linux/slab.h:517 [inline] map_get_next_key+0x24a/0x640 kernel/bpf/syscall.c:858 __do_sys_bpf kernel/bpf/syscall.c:2131 [inline] __se_sys_bpf kernel/bpf/syscall.c:2096 [inline] __x64_sys_bpf+0x354/0x4f0 kernel/bpf/syscall.c:2096 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe The test case is against sock hashmap with a key size 0xffffffe1. Such a large key size will cause the below code in function sock_hash_alloc() overflowing and produces a smaller elem_size, hence map creation will be successful. htab->elem_size = sizeof(struct htab_elem) + round_up(htab->map.key_size, 8); Later, when map_get_next_key is called and kernel tries to allocate the key unsuccessfully, it will issue the above warning. Similar to hashtab, ensure the key size is at most MAX_BPF_STACK for a successful map creation. Fixes: 81110384441a ("bpf: sockmap, add hash map support") Reported-by: syzbot+e4566d29080e7f3460ff@syzkaller.appspotmail.com Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.