[syzbot] KMSAN: uninit-value in cma_make_mc_event

[syzbot] KMSAN: uninit-value in cma_make_mc_event

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8b936c96768e kmsan: core: remove the accidentally committe..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=13420bb9b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e00a8959fdd3f3e8
dashboard link: https://syzkaller.appspot.com/bug?extid=8fcbb77276d43cc8b693
compiler:       clang version 14.0.0 (git@github.com:llvm/llvm-project.git 0996585c8e3b3d409494eb5f1cad714b9e1f7fb5), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

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+8fcbb77276d43cc8b693@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in cma_set_qkey drivers/infiniband/core/cma.c:510 [inline]
BUG: KMSAN: uninit-value in cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570
 cma_set_qkey drivers/infiniband/core/cma.c:510 [inline]
 cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570
 cma_iboe_join_multicast drivers/infiniband/core/cma.c:4782 [inline]
 rdma_join_multicast+0x2b83/0x30a0 drivers/infiniband/core/cma.c:4814
 ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479
 ucma_join_multicast+0x1e3/0x250 drivers/infiniband/core/ucma.c:1546
 ucma_write+0x639/0x6d0 drivers/infiniband/core/ucma.c:1732
 vfs_write+0x8ce/0x2030 fs/read_write.c:588
 ksys_write+0x28c/0x520 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __ia32_sys_write+0xdb/0x120 fs/read_write.c:652
 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
 __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable ib.i created at:
 cma_iboe_join_multicast drivers/infiniband/core/cma.c:4737 [inline]
 rdma_join_multicast+0x586/0x30a0 drivers/infiniband/core/cma.c:4814
 ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479

CPU: 0 PID: 29874 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================


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