Messages in this thread | | | From | Xin Long <> | Date | Mon, 31 Oct 2022 22:20:53 -0400 | Subject | Re: BUG: unable to handle kernel NULL pointer dereference in tipc_conn_close |
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On Sun, Oct 30, 2022 at 6:20 AM Wei Chen <harperchen1110@gmail.com> wrote: > > Dear Linux Developer, > > Recently when using our tool to fuzz kernel, the following crash was triggered: > > HEAD commit: 64570fbc14f8 Linux 5.15-rc5 > git tree: upstream > compiler: gcc 8.0.1 > console output: > https://drive.google.com/file/d/1nDvjcSyhzWncMlR35k1P1dC8rswJ_Zin/view?usp=share_link > kernel config: https://drive.google.com/file/d/1uDOeEYgJDcLiSOrx9W8v2bqZ6uOA_55t/view?usp=share_link > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: Wei Chen <harperchen1110@gmail.com> > > BUG: kernel NULL pointer dereference, address: 0000000000000018 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP > CPU: 1 PID: 7336 Comm: kworker/u4:4 Not tainted 5.15.0-rc5 #1 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 > Workqueue: netns cleanup_net > RIP: 0010:tipc_conn_close+0x12/0x100 con->sock is set only after tipc_topsrv_accept() is called by awork. We should do the check under a proper lock.
Will think about it, thanks.
> Code: 02 01 e8 52 74 20 00 e9 c6 fd ff ff 66 90 66 2e 0f 1f 84 00 00 > 00 00 00 41 55 41 54 55 53 48 89 fb e8 82 4f c2 fc 48 8b 43 08 <4c> 8b > 68 18 4d 8d a5 b0 03 00 00 4c 89 e7 e8 fb 36 44 00 f0 48 0f > RSP: 0018:ffffc90005137d60 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffff88805a9eea00 RCX: ffff88810b035280 > RDX: 0000000000000000 RSI: ffff88810b035280 RDI: 0000000000000002 > RBP: ffffc90005137db0 R08: ffffffff847b23de R09: 0000000000000001 > R10: 0000000000000005 R11: 0000000000000000 R12: ffff88810bdeed40 > R13: 000000000000027b R14: ffff88805a9eea00 R15: ffff88810ebc2058 > FS: 0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000018 CR3: 000000010b0e2000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > tipc_topsrv_exit_net+0x139/0x320 > ops_exit_list.isra.9+0x49/0x80 > cleanup_net+0x31a/0x540 > process_one_work+0x3fa/0x9f0 > worker_thread+0x42/0x5c0 > kthread+0x1a6/0x1e0 > ret_from_fork+0x1f/0x30 > Modules linked in: > CR2: 0000000000000018 > ---[ end trace 1524bb8c4ed3c3b4 ]--- > RIP: 0010:tipc_conn_close+0x12/0x100 > Code: 02 01 e8 52 74 20 00 e9 c6 fd ff ff 66 90 66 2e 0f 1f 84 00 00 > 00 00 00 41 55 41 54 55 53 48 89 fb e8 82 4f c2 fc 48 8b 43 08 <4c> 8b > 68 18 4d 8d a5 b0 03 00 00 4c 89 e7 e8 fb 36 44 00 f0 48 0f > RSP: 0018:ffffc90005137d60 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffff88805a9eea00 RCX: ffff88810b035280 > RDX: 0000000000000000 RSI: ffff88810b035280 RDI: 0000000000000002 > RBP: ffffc90005137db0 R08: ffffffff847b23de R09: 0000000000000001 > R10: 0000000000000005 R11: 0000000000000000 R12: ffff88810bdeed40 > R13: 000000000000027b R14: ffff88805a9eea00 R15: ffff88810ebc2058 > FS: 0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000018 CR3: 000000010b0e2000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 02 01 add (%rcx),%al > 2: e8 52 74 20 00 callq 0x207459 > 7: e9 c6 fd ff ff jmpq 0xfffffdd2 > c: 66 90 xchg %ax,%ax > e: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) > 15: 00 00 00 > 18: 41 55 push %r13 > 1a: 41 54 push %r12 > 1c: 55 push %rbp > 1d: 53 push %rbx > 1e: 48 89 fb mov %rdi,%rbx > 21: e8 82 4f c2 fc callq 0xfcc24fa8 > 26: 48 8b 43 08 mov 0x8(%rbx),%rax > * 2a: 4c 8b 68 18 mov 0x18(%rax),%r13 <-- trapping instruction > 2e: 4d 8d a5 b0 03 00 00 lea 0x3b0(%r13),%r12 > 35: 4c 89 e7 mov %r12,%rdi > 38: e8 fb 36 44 00 callq 0x443738 > 3d: f0 lock > 3e: 48 rex.W > 3f: 0f .byte 0xf > > Best, > Wei
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