KMSAN: uninit-value in af_alg_free_areq_sgls
From: syzbot <hidden>
Date: 2018-04-08 07:07:03
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Hello, syzbot hit the following crash on https://github.com/google/kmsan.git/master commit e2ab7e8abba47a2f2698216258e5d8727ae58717 (Fri Apr 6 16:24:31 2018 +0000) kmsan: temporarily disable visitAsmInstruction() to help syzbot syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=9c251bdd09f83b92ba95 So far this crash happened 11 times on https://github.com/google/kmsan.git/master. C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5551473324720128 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=4782073151750144 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=5003160619843584 Kernel config: https://syzkaller.appspot.com/x/.config?id=6627248707860932248 compiler: clang version 7.0.0 (trunk 329391) IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+9c251bdd09f83b92ba95@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer. ================================================================== BUG: KMSAN: uninit-value in atomic_sub arch/x86/include/asm/atomic.h:65 [inline] BUG: KMSAN: uninit-value in af_alg_free_areq_sgls+0x5ff/0xb20 crypto/af_alg.c:669 CPU: 1 PID: 3568 Comm: syzkaller909997 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 atomic_sub arch/x86/include/asm/atomic.h:65 [inline] af_alg_free_areq_sgls+0x5ff/0xb20 crypto/af_alg.c:669 af_alg_free_resources+0x66/0xf0 crypto/af_alg.c:1033 _aead_recvmsg crypto/algif_aead.c:321 [inline] aead_recvmsg+0x9a4/0x2960 crypto/algif_aead.c:334 aead_recvmsg_nokey+0x129/0x160 crypto/algif_aead.c:452 sock_recvmsg_nosec net/socket.c:803 [inline] sock_recvmsg+0x1d0/0x230 net/socket.c:810 ___sys_recvmsg+0x3fb/0x810 net/socket.c:2205 __sys_recvmsg net/socket.c:2250 [inline] SYSC_recvmsg+0x298/0x3c0 net/socket.c:2262 SyS_recvmsg+0x54/0x80 net/socket.c:2257 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x43ff29 RSP: 002b:00007ffd9919c808 EFLAGS: 00000207 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ff29 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000004 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000207 R12: 0000000000401850 R13: 00000000004018e0 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 __kmalloc+0x23c/0x350 mm/slub.c:3791 kmalloc include/linux/slab.h:517 [inline] sock_kmalloc+0x14e/0x270 net/core/sock.c:1986 af_alg_get_rsgl+0x427/0xe10 crypto/af_alg.c:1149 _aead_recvmsg crypto/algif_aead.c:163 [inline] aead_recvmsg+0x953/0x2960 crypto/algif_aead.c:334 aead_recvmsg_nokey+0x129/0x160 crypto/algif_aead.c:452 sock_recvmsg_nosec net/socket.c:803 [inline] sock_recvmsg+0x1d0/0x230 net/socket.c:810 ___sys_recvmsg+0x3fb/0x810 net/socket.c:2205 __sys_recvmsg net/socket.c:2250 [inline] SYSC_recvmsg+0x298/0x3c0 net/socket.c:2262 SyS_recvmsg+0x54/0x80 net/socket.c:2257 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 ================================================================== --- This bug is generated by a dumb bot. It may contain errors. See https://goo.gl/tpsmEJ for details. Direct all questions to syzkaller@googlegroups.com. syzbot will keep track of this bug report. If you forgot to add the Reported-by tag, once the fix for this bug is merged into any tree, please reply to this email with: #syz fix: exact-commit-title If you want to test a patch for this bug, please reply with: #syz test: git://repo/address.git branch and provide the patch inline or as an attachment. To mark this as a duplicate of another syzbot report, please reply with: #syz dup: exact-subject-of-another-report If it's a one-off invalid bug report, please reply with: #syz invalid Note: if the crash happens again, it will cause creation of a new bug report. Note: all commands must start from beginning of the line in the email body.