linux-kernel - [linus:master] [mm] 24e44cc22a: BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint

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Message-ID: <202407191651.f24e499d-oliver.sang@intel.com>
Date: Mon, 22 Jul 2024 15:30:01 +0800
From: kernel test robot <oliver.sang@...el.com>
To: Suren Baghdasaryan <surenb@...gle.com>
CC: <oe-lkp@...ts.linux.dev>, <lkp@...el.com>, <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>, Kent Overstreet
	<kent.overstreet@...ux.dev>, Kees Cook <keescook@...omium.org>, "Alexander
 Viro" <viro@...iv.linux.org.uk>, Alex Gaynor <alex.gaynor@...il.com>, "Alice
 Ryhl" <aliceryhl@...gle.com>, Andreas Hindborg <a.hindborg@...sung.com>,
	"Benno Lossin" <benno.lossin@...ton.me>, Björn Roy Baron
	<bjorn3_gh@...tonmail.com>, Boqun Feng <boqun.feng@...il.com>, "Christoph
 Lameter" <cl@...ux.com>, Dennis Zhou <dennis@...nel.org>, Gary Guo
	<gary@...yguo.net>, Miguel Ojeda <ojeda@...nel.org>, Pasha Tatashin
	<pasha.tatashin@...een.com>, Peter Zijlstra <peterz@...radead.org>, Tejun Heo
	<tj@...nel.org>, Vlastimil Babka <vbabka@...e.cz>, Wedson Almeida Filho
	<wedsonaf@...il.com>, <linux-mm@...ck.org>, <oliver.sang@...el.com>
Subject: [linus:master] [mm]  24e44cc22a:
 BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc



Hello,

kernel test robot noticed "BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc" on:

commit: 24e44cc22aa3112082f2ee23137d048c73ca96d5 ("mm: percpu: enable per-cpu allocation tagging")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

[test failed on linus/mater       68b59730459e5d1fe4e0bbeb04ceb9df0f002270]
[test failed on linux-next/master 73399b58e5e5a1b28a04baf42e321cfcfc663c2f]

in testcase: trinity
version: trinity-i386-abe9de86-1_20230429
with following parameters:

	runtime: 300s
	group: group-04
	nr_groups: 5



compiler: gcc-13
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)


as we understand, this commit is not the root-cause of KCSAN issue, just make
the issue change from form (1) to (2). furthermore, we don't understand why
the issue happens randomly. but we failed to bisect the issue (1). so we just
make out this report FYI, not sure if it could supply some hints to any real
issues.

60fa4a9e23231721 24e44cc22aa3112082f2ee23137
---------------- ---------------------------
       fail:runs  %reproduction    fail:runs
           |             |             |
        281:999        -28%            :998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_alloc   <--- (1)
        296:999        -30%            :998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_free
         25:999         -3%            :998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_chunk_populated
           :999         29%         292:998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc   <---(2)
           :999         27%         269:998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_free
           :999          4%          44:998   dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_chunk_populated



If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@...el.com>
| Closes: https://lore.kernel.org/oe-lkp/202407191651.f24e499d-oliver.sang@intel.com



[  117.357897][ T3648] ==================================================================
[  117.358568][ T3648] BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_block_update_hint_alloc
[  117.359222][ T3648]
[  117.359424][ T3648] write to 0xffffffff8559e600 of 4 bytes by task 3653 on cpu 1:
[ 117.360048][ T3648] pcpu_block_update_hint_alloc (mm/percpu.c:602 mm/percpu.c:598 mm/percpu.c:923) 
[ 117.360554][ T3648] pcpu_alloc_area (mm/percpu.c:1260) 
[ 117.360960][ T3648] pcpu_alloc_noprof (mm/percpu.c:1835) 
[ 117.361393][ T3648] bpf_map_alloc_percpu (kernel/bpf/syscall.c:466) 
[ 117.361825][ T3648] prealloc_init (kernel/bpf/hashtab.c:338) 
[ 117.362211][ T3648] htab_map_alloc (kernel/bpf/hashtab.c:573) 
[ 117.362618][ T3648] map_create (kernel/bpf/syscall.c:1320) 
[ 117.362987][ T3648] __sys_bpf (kernel/bpf/syscall.c:5642) 
[ 117.363348][ T3648] __ia32_sys_bpf (kernel/bpf/syscall.c:5765) 
[ 117.363738][ T3648] ia32_sys_call (kbuild/obj/consumer/x86_64-randconfig-013-20240713/./arch/x86/include/generated/asm/syscalls_32.h:358) 
[ 117.364151][ T3648] do_int80_emulation (arch/x86/entry/common.c:165 (discriminator 1) arch/x86/entry/common.c:253 (discriminator 1)) 
[ 117.364578][ T3648] asm_int80_emulation (arch/x86/include/asm/idtentry.h:626) 
[  117.365004][ T3648]
[  117.365203][ T3648] read to 0xffffffff8559e600 of 4 bytes by task 3648 on cpu 0:
[ 117.365797][ T3648] pcpu_alloc_noprof (mm/percpu.c:1894) 
[ 117.366210][ T3648] bpf_map_alloc_percpu (kernel/bpf/syscall.c:466) 
[ 117.366627][ T3648] prealloc_init (kernel/bpf/hashtab.c:338) 
[ 117.367000][ T3648] htab_map_alloc (kernel/bpf/hashtab.c:573) 
[ 117.367400][ T3648] map_create (kernel/bpf/syscall.c:1320) 
[ 117.367766][ T3648] __sys_bpf (kernel/bpf/syscall.c:5642) 
[ 117.368120][ T3648] __ia32_sys_bpf (kernel/bpf/syscall.c:5765) 
[ 117.368503][ T3648] ia32_sys_call (kbuild/obj/consumer/x86_64-randconfig-013-20240713/./arch/x86/include/generated/asm/syscalls_32.h:358) 
[ 117.368907][ T3648] do_int80_emulation (arch/x86/entry/common.c:165 (discriminator 1) arch/x86/entry/common.c:253 (discriminator 1)) 
[ 117.369341][ T3648] asm_int80_emulation (arch/x86/include/asm/idtentry.h:626) 
[  117.369761][ T3648]
[  117.369968][ T3648] value changed: 0x00000003 -> 0x00000000
[  117.370454][ T3648]
[  117.370662][ T3648] Reported by Kernel Concurrency Sanitizer on:
[  117.371179][ T3648] CPU: 0 PID: 3648 Comm: trinity-c2 Not tainted 6.9.0-rc4-00089-g24e44cc22aa3 #1
[  117.371943][ T3648] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[  117.372811][ T3648] ==================================================================



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20240719/202407191651.f24e499d-oliver.sang@intel.com



-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki