On 12/31/20 4:49 AM, Linus Torvalds wrote:
On Tue, Dec 29, 2020 at 6:59 PM kernel test robot <oliver.s...@intel.com> wrote:
[ 235.553325] BUG: sleeping function called from invalid context at
arch/x86/mm/fault.c:1351
[ 235.554684] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 7515,
name: trinity-c1
[ 235.555890] 2 locks held by trinity-c1/7515:
[ 235.556506] #0: ffffffff8323dd38 (&ids->rwsem){....}-{3:3}, at:
semctl_down+0x6d/0x686
[ 235.557684] #1: ffff888128ccc868 (&mm->mmap_lock#2){....}-{3:3}, at:
do_user_addr_fault+0x196/0x59e
[ 235.559020] CPU: 1 PID: 7515 Comm: trinity-c1 Not tainted
5.10.0-g97593cad003c #2
[ 235.560317] Call Trace:
[ 235.560767] dump_stack+0x7d/0xa3
[ 235.561371] ___might_sleep+0x2c4/0x2df
[ 235.562063] ? do_user_addr_fault+0x196/0x59e
[ 235.562834] do_user_addr_fault+0x234/0x59e
[ 235.563519] exc_page_fault+0x70/0x8b
[ 235.564112] asm_exc_page_fault+0x1b/0x20
Btw, I wonder if the kernel test robot dumps could be please run through the
scripts/decode_stacktrace.sh
script to give line numbers and inlining information?
That does require CONFIG_DEBUG_INFO to work, but it would help things
like this when you don't have to try to guess where the exact access
happens.
Now, in this case, it seems to be a recursive issue with the original
fault happening in:
[ 235.564754] RIP: 0010:kasan_record_aux_stack+0x64/0x74
And yeah, that explains why it then bisects to 97593cad003c ("kasan:
sanitize objects when metadata doesn't fit")
The faulting instruction sequence decodes to
10: 48 39 f3 cmp %rsi,%rbx
13: 48 0f 46 f3 cmovbe %rbx,%rsi
17: e8 6f e5 ff ff callq .. something ..
1c: bf 00 08 00 00 mov $0x800,%edi
21: 48 89 c3 mov %rax,%rbx
24:* 8b 40 08 mov 0x8(%rax),%eax <--
trapping instruction
27: 89 43 0c mov %eax,0xc(%rbx)
and I *think* that "call something" is the call to
kasan_get_alloc_meta. And there is no check for a NULL return.
So I think this was already fixed by commit 13384f6125ad ("kasan: fix
null pointer dereference in kasan_record_aux_stack").
But see about that "decode_stacktrace,sh" script request. I thought I
had already asked for this, but I now realize that I think that was
just for syzbot.
Can we do that for these kernel test robot reports too? Please?
Linus
Hi Linus,
Sorry for the inconvenience and we're working on it right now.
Happy New Year!
Best Regards,
Rong Chen
