On Thu, 07 Oct 2021 13:28:29 +0000 Jordan Glover wrote: > >For me above patch changed slightly the printed output. Now the warning >comes from 'cleanup_net' instead of 'free_user_ns'. My system was also >still responsive after the bug occurred which didn't happen previously. >I can't say if this means anything or if this is result of above patch >or instability of my reproducer. Thanks for your report. It is the same issue as reported before and my patch did not help. Hillf > >------------[ cut here ]------------ >WARNING: CPU: 2 PID: 27643 at kernel/ucount.c:256 dec_ucount+0x43/0x50 >Modules linked in: <cut> >CPU: 2 PID: 27643 Comm: kworker/u8:3 Not tainted 5.14.9 #1 0274f3d0712a6dad= >c9a2cf8341ae333de732a31a >Workqueue: netns cleanup_net >RIP: 0010:dec_ucount+0x43/0x50 >Code: 14 01 48 8b 02 48 89 c6 48 83 ee 01 78 1c f0 48 0f b1 32 75 f0 48 8b = >41 10 48 8b 88 e8 01 00 00 48 85 c9 75 d9 e9 fd fc ff ff <0f> 0b eb e7 66 0= >f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 f8 48 >RSP: 0018:ffffb34fc34cfe30 EFLAGS: 00010297 >RAX: 0000000000000000 RBX: ffffa448eec5f3b0 RCX: ffffa447cfe1f540 >RDX: ffffa447cfe1f580 RSI: ffffffffffffffff RDI: ffffa447c445c780 >RBP: ffffa448eec5f380 R08: 0000000000000040 R09: ffffa44a196ac040 >R10: 00000000001436be R11: 0000000000000259 R12: ffffb34fc34cfe10 >R13: ffffb34fc34cfe40 R14: 00000000ffffffff R15: ffffa448eec5d414 >FS: 0000000000000000(0000) GS:ffffa44a19700000(0000) knlGS:000000000000000= >0 >CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >CR2: 000072a95d359030 CR3: 000000000b20e005 CR4: 00000000003706e0 >DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >Call Trace: > cleanup_net+0x2e2/0x370 > process_one_work+0x1e1/0x380 > worker_thread+0x50/0x3a0 > ? rescuer_thread+0x360/0x360 > kthread+0x127/0x150 > ? set_kthread_struct+0x40/0x40 > ret_from_fork+0x22/0x30 >---[ end trace e5fdc3317f00d0e8 ]--- >BUG: kernel NULL pointer dereference, address: 00000000000001e8 >#PF: supervisor read access in kernel mode >#PF: error_code(0x0000) - not-present page >PGD 0 P4D 0 >Oops: 0000 [#1] SMP PTI >CPU: 2 PID: 27643 Comm: kworker/u8:3 Tainted: G W 5.14.9 #1 = >0274f3d0712a6dadc9a2cf8341ae333de732a31a >Workqueue: netns cleanup_net >RIP: 0010:dec_ucount+0x32/0x50 >Code: 74 34 89 f6 48 89 f9 4c 8d 04 f5 20 00 00 00 4a 8d 14 01 48 8b 02 48 = >89 c6 48 83 ee 01 78 1c f0 48 0f b1 32 75 f0 48 8b 41 10 <48> 8b 88 e8 01 0= >0 00 48 85 c9 75 d9 e9 fd fc ff ff 0f 0b eb e7 66 >RSP: 0018:ffffb34fc34cfe30 EFLAGS: 00010297 >RAX: 0000000000000000 RBX: ffffa448eec5f3b0 RCX: ffffa447cfe1f540 >RDX: ffffa447cfe1f580 RSI: ffffffffffffffff RDI: ffffa447c445c780 >RBP: ffffa448eec5f380 R08: 0000000000000040 R09: ffffa44a196ac040 >R10: 00000000001436be R11: 0000000000000259 R12: ffffb34fc34cfe10 >R13: ffffb34fc34cfe40 R14: 00000000ffffffff R15: ffffa448eec5d414 >FS: 0000000000000000(0000) GS:ffffa44a19700000(0000) knlGS:000000000000000= >0 >CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >CR2: 00000000000001e8 CR3: 000000000b20e005 CR4: 00000000003706e0 >DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >Call Trace: > cleanup_net+0x2e2/0x370 > process_one_work+0x1e1/0x380 > worker_thread+0x50/0x3a0 > ? rescuer_thread+0x360/0x360 > kthread+0x127/0x150 > ? set_kthread_struct+0x40/0x40 > ret_from_fork+0x22/0x30 >Modules linked in: <cut> >CR2: 00000000000001e8 >---[ end trace e5fdc3317f00d0e9 ]--- >RIP: 0010:dec_ucount+0x32/0x50 >Code: 74 34 89 f6 48 89 f9 4c 8d 04 f5 20 00 00 00 4a 8d 14 01 48 8b 02 48 = >89 c6 48 83 ee 01 78 1c f0 48 0f b1 32 75 f0 48 8b 41 10 <48> 8b 88 e8 01 0= >0 00 48 85 c9 75 d9 e9 fd fc ff ff 0f 0b eb e7 66 >RSP: 0018:ffffb34fc34cfe30 EFLAGS: 00010297 >RAX: 0000000000000000 RBX: ffffa448eec5f3b0 RCX: ffffa447cfe1f540 >RDX: ffffa447cfe1f580 RSI: ffffffffffffffff RDI: ffffa447c445c780 >RBP: ffffa448eec5f380 R08: 0000000000000040 R09: ffffa44a196ac040 >R10: 00000000001436be R11: 0000000000000259 R12: ffffb34fc34cfe10 >R13: ffffb34fc34cfe40 R14: 00000000ffffffff R15: ffffa448eec5d414 >FS: 0000000000000000(0000) GS:ffffa44a19700000(0000) knlGS:000000000000000= >0 >CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >CR2: 00000000000001e8 CR3: 000000000b20e005 CR4: 00000000003706e0 >DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > >
