Messages in this thread | | | From | Marco Elver <> | Date | Tue, 4 May 2021 13:38:20 +0200 | Subject | Re: [syzbot] KCSAN: data-race in assoc_array_apply_edit / search_nested_keyrings |
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Hello,
On Tue, 4 May 2021 at 13:33, syzbot <syzbot+e4eb6db47eb0f80308c6@syzkaller.appspotmail.com> wrote: > HEAD commit: 5e321ded Merge tag 'for-5.13/parisc' of git://git.kernel.o.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=111cafb9d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a4da2ebcb6e8f526 > dashboard link: https://syzkaller.appspot.com/bug?extid=e4eb6db47eb0f80308c6 > compiler: Debian clang version 11.0.1-2 > > 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+e4eb6db47eb0f80308c6@syzkaller.appspotmail.com > > ================================================================== > BUG: KCSAN: data-race in assoc_array_apply_edit / search_nested_keyrings > > write to 0xffff8881065ffc10 of 8 bytes by task 30966 on cpu 1: > assoc_array_apply_edit+0x3e/0x660 lib/assoc_array.c:1357 > __key_link+0x8a/0xc0 security/keys/keyring.c:1372 > __key_instantiate_and_link+0x15b/0x290 security/keys/key.c:459 > key_create_or_update+0x750/0x990 security/keys/key.c:941 > __do_sys_add_key security/keys/keyctl.c:134 [inline] > __se_sys_add_key+0x26f/0x300 security/keys/keyctl.c:74 > __x64_sys_add_key+0x63/0x70 security/keys/keyctl.c:74 > do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > read to 0xffff8881065ffc10 of 8 bytes by task 30971 on cpu 0: > search_nested_keyrings+0x34f/0x920 security/keys/keyring.c:751 > keyring_search_rcu+0xf4/0x180 security/keys/keyring.c:922 > search_cred_keyrings_rcu+0x135/0x240 security/keys/process_keys.c:480 > search_process_keyrings_rcu security/keys/process_keys.c:544 [inline] > lookup_user_key+0xab6/0xd40 security/keys/process_keys.c:762 > __do_sys_add_key security/keys/keyctl.c:126 [inline] > __se_sys_add_key+0x23a/0x300 security/keys/keyctl.c:74 > __x64_sys_add_key+0x63/0x70 security/keys/keyctl.c:74 > do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 > entry_SYSCALL_64_after_hwframe+0x44/0xae
I found this interesting because the code around security/keys/keyring.c:751 is diligent in marking concurrency accesses with READ_ONCE(). So on the off-chance there is unexpected concurrency here, I thought it'd be worth double-checking as I wasn't able to conclude if this is just missing a READ_ONCE().
Thank you!
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