[+Cc Matthew Wilcox] Possibly a bug in lib/radix-tree.c? this_cpu_ptr() in radix_tree_node_alloc() can be reached without a prior preempt_disable(). Or is the caller of idr_alloc() doing something wrong?
On Thu, Jun 04, 2020 at 07:02:18PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: acf25aa6 Merge tag 'Smack-for-5.8' of git://github.com/csc.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13d6307a100000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5263d9b5bce03c67 > dashboard link: https://syzkaller.appspot.com/bug?extid=3eec59e770685e3dc879 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15bd4c1e100000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1520c9de100000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+3eec59e770685e3dc...@syzkaller.appspotmail.com > > RAX: ffffffffffffffda RBX: 00007ffdf01d56d0 RCX: 00000000004406c9 > RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 > RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000031 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401f50 > R13: 0000000000401fe0 R14: 0000000000000000 R15: 0000000000000000 > BUG: using smp_processor_id() in preemptible [00000000] code: > syz-executor036/6796 > caller is radix_tree_node_alloc.constprop.0+0x200/0x330 lib/radix-tree.c:262 > CPU: 0 PID: 6796 Comm: syz-executor036 Not tainted 5.7.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x188/0x20d lib/dump_stack.c:118 > check_preemption_disabled lib/smp_processor_id.c:47 [inline] > debug_smp_processor_id.cold+0x88/0x9b lib/smp_processor_id.c:57 > radix_tree_node_alloc.constprop.0+0x200/0x330 lib/radix-tree.c:262 > radix_tree_extend+0x256/0x4e0 lib/radix-tree.c:424 > idr_get_free+0x60c/0x8e0 lib/radix-tree.c:1492 > idr_alloc_u32+0x170/0x2d0 lib/idr.c:46 > idr_alloc+0xc2/0x130 lib/idr.c:87 > qrtr_port_assign net/qrtr/qrtr.c:703 [inline] > __qrtr_bind.isra.0+0x12e/0x5c0 net/qrtr/qrtr.c:756 > qrtr_autobind net/qrtr/qrtr.c:787 [inline] > qrtr_autobind+0xaf/0xf0 net/qrtr/qrtr.c:775 > qrtr_sendmsg+0x1d6/0x770 net/qrtr/qrtr.c:895 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:672 > ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352 > ___sys_sendmsg+0x100/0x170 net/socket.c:2406 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 > entry_SYSCALL_64_after_hwframe+0x49/0xb3 > RIP: 0033:0x4406c9 > Code: 25 02 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 90 48 89 f8 48 89 f7 48 > 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f > 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffdf01d56c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00007ffdf01d56d0 RCX: 00000000004406c9 > RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 > RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000031 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401f50 > R13: 0000000000401fe0 R14: 0000000000000000 R15: 0000000000000000 > > > --- > This bug 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 syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches >
