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* [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp
@ 2024-03-10  9:16 syzbot
  2024-07-01 10:17 ` [syzbot] " syzbot
  0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2024-03-10  9:16 UTC (permalink / raw)
  To: andrii, ast, bpf, daniel, davem, edumazet, haoluo, john.fastabend,
	jolsa, kpsingh, kuba, linux-kernel, martin.lau, netdev, pabeni,
	sdf, song, syzkaller-bugs, yonghong.song

Hello,

syzbot found the following issue on:

HEAD commit:    3aaa8ce7a335 Merge tag 'mm-hotfixes-stable-2024-03-07-16-1..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13e5861e180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f8d2f8f66e9a667a
dashboard link: https://syzkaller.appspot.com/bug?extid=6856926fbb5e9b794e5c
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10ed8171180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13b728ae180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2a093f1b5a72/disk-3aaa8ce7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/efa5cb929ca6/vmlinux-3aaa8ce7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2b0c044e721b/bzImage-3aaa8ce7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6856926fbb5e9b794e5c@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in bpf_prog_test_run_xdp+0x1758/0x1a30 net/bpf/test_run.c:1277
 bpf_prog_test_run_xdp+0x1758/0x1a30 net/bpf/test_run.c:1277
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 bpf_test_run+0x515/0xaf0
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 ___bpf_prog_run+0x76dd/0xdb80
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 ___bpf_prog_run+0x8567/0xdb80
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421
 bpf_prog_test_run_xdp+0xea5/0x1a30 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x6af/0xac0 kernel/bpf/syscall.c:4107
 __sys_bpf+0x649/0xd60 kernel/bpf/syscall.c:5475
 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5559 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5559
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Local variable stack created at:
 __bpf_prog_run512+0x45/0xe0 kernel/bpf/core.c:2227
 bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline]
 __bpf_prog_run include/linux/filter.h:651 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x42d/0xaf0 net/bpf/test_run.c:421

CPU: 0 PID: 5009 Comm: syz-executor369 Not tainted 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
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#syz dup: exact-subject-of-another-report

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#syz undup

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [syzbot] [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp
  2024-03-10  9:16 [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp syzbot
@ 2024-07-01 10:17 ` syzbot
  0 siblings, 0 replies; 3+ messages in thread
From: syzbot @ 2024-07-01 10:17 UTC (permalink / raw)
  To: linux-kernel, syzkaller-bugs

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp
Author: wojciech.gladysz@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux e478cf26c556e4ab572ab0ab2306c986901dcd61

---
 kernel/bpf/verifier.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 36ef8e96787e..13a9c2e2908a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7146,8 +7146,8 @@ static int check_stack_range_initialized(
 		 * reads. However, if raw_mode is not set, we'll do extra
 		 * checks below.
 		 */
-		bounds_check_type = BPF_WRITE;
-		clobber = true;
+		clobber = !meta || meta->raw_mode;
+		bounds_check_type = clobber ? BPF_WRITE : BPF_READ;
 	} else {
 		bounds_check_type = BPF_READ;
 	}
@@ -7230,8 +7230,7 @@ static int check_stack_range_initialized(
 		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
 		if (*stype == STACK_MISC)
 			goto mark;
-		if ((*stype == STACK_ZERO) ||
-		    (*stype == STACK_INVALID && env->allow_uninit_stack)) {
+		if (*stype == STACK_ZERO) {
 			if (clobber) {
 				/* helper can write anything into the stack */
 				*stype = STACK_MISC;
@@ -8748,6 +8747,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		meta->map_uid = reg->map_uid;
 		break;
 	case ARG_PTR_TO_MAP_KEY:
+		/* always mark read access */
+		meta->raw_mode = false;
 		/* bpf_map_xxx(..., map_ptr, ..., key) call:
 		 * check that [key, key + map->key_size) are within
 		 * stack limits and initialized
@@ -8763,7 +8764,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		}
 		err = check_helper_mem_access(env, regno,
 					      meta->map_ptr->key_size, false,
-					      NULL);
+					      meta);
 		break;
 	case ARG_PTR_TO_MAP_VALUE:
 		if (type_may_be_null(arg_type) && register_is_null(reg))
-- 
2.35.3

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp
       [not found] <20240701101742.15473-1-wojciech.gladysz@infogain.com>
@ 2024-07-01 12:40 ` syzbot
  0 siblings, 0 replies; 3+ messages in thread
From: syzbot @ 2024-07-01 12:40 UTC (permalink / raw)
  To: linux-kernel, syzkaller-bugs, wojciech.gladysz

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in bpf_prog_test_run_xdp

=====================================================
BUG: KMSAN: uninit-value in bpf_prog_test_run_xdp+0x175d/0x1a40 net/bpf/test_run.c:1287
 bpf_prog_test_run_xdp+0x175d/0x1a40 net/bpf/test_run.c:1287
 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5736
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
 bpf_test_run+0x52e/0xc30
 bpf_prog_test_run_xdp+0xeaa/0x1a40 net/bpf/test_run.c:1277
 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5736
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
 ___bpf_prog_run+0x58c4/0xe0f0
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2252
 bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
 __bpf_prog_run include/linux/filter.h:667 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x43e/0xc30 net/bpf/test_run.c:423
 bpf_prog_test_run_xdp+0xeaa/0x1a40 net/bpf/test_run.c:1277
 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5736
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
 ___bpf_prog_run+0x9098/0xe0f0
 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2252
 bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
 __bpf_prog_run include/linux/filter.h:667 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x43e/0xc30 net/bpf/test_run.c:423
 bpf_prog_test_run_xdp+0xeaa/0x1a40 net/bpf/test_run.c:1277
 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5736
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Local variable stack created at:
 __bpf_prog_run512+0x45/0xe0 kernel/bpf/core.c:2252
 bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
 __bpf_prog_run include/linux/filter.h:667 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x43e/0xc30 net/bpf/test_run.c:423

CPU: 0 PID: 5442 Comm: syz-executor.0 Not tainted 6.9.0-rc1-syzkaller-00257-ge478cf26c556-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
=====================================================


Tested on:

commit:         e478cf26 Merge branch 'bpf-fix-a-couple-of-test-failur..
git tree:       https://linux.googlesource.com/linux/kernel/git/torvalds/linux
console output: https://syzkaller.appspot.com/x/log.txt?x=14d7871e980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795
dashboard link: https://syzkaller.appspot.com/bug?extid=6856926fbb5e9b794e5c
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=162e5ed1980000


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2024-07-01 12:40 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-03-10  9:16 [syzbot] [bpf?] [net?] KMSAN: uninit-value in bpf_prog_test_run_xdp syzbot
2024-07-01 10:17 ` [syzbot] " syzbot
     [not found] <20240701101742.15473-1-wojciech.gladysz@infogain.com>
2024-07-01 12:40 ` syzbot

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