> > > syzbot has found a reproducer for the following issue on: > > > > > > HEAD commit: ab8be66e Add linux-next specific files for 20200720 > > > git tree: linux-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=161a0cc8900000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=c4bf77d63d0cf88c > > > dashboard link: https://syzkaller.appspot.com/bug?extid=5f326d255ca648131f87 > > > compiler: gcc (GCC) 10.1.0-syz 20200507 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=151192bb100000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12d7a873100000 > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+5f326d255ca648131f87@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > > > ------------[ cut here ]------------ > > > kernel BUG at mm/vmalloc.c:3089! > > > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > > > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.8.0-rc6-next-20200720-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > > Workqueue: events pcpu_balance_workfn > > > RIP: 0010:free_vm_area mm/vmalloc.c:3089 [inline] > > > RIP: 0010:free_vm_area mm/vmalloc.c:3085 [inline] > > > RIP: 0010:pcpu_free_vm_areas+0x96/0xc0 mm/vmalloc.c:3432 > > > Code: 75 48 48 8b 2b 48 8d 7d 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 75 2c 48 8b 7d 08 e8 c4 c8 ff ff 48 39 c5 74 a5 e8 ea c3 c9 ff <0f> 0b e8 e3 c3 c9 ff 4c 89 ff 5b 5d 41 5c 41 5d 41 5e 41 5f e9 71 > > > RSP: 0018:ffffc90000d2fba8 EFLAGS: 00010293 > > > RAX: 0000000000000000 RBX: ffff8880a801be00 RCX: 0000000000000000 > > > RDX: ffff8880a95fa300 RSI: ffffffff81aa7c76 RDI: 0000000000000001 > > > RBP: ffff8880a2b38180 R08: 0000000000000000 R09: ffffffff89cfecc3 > > > R10: fffffbfff139fd98 R11: 0000000000000000 R12: 0000000000000000 > > > R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880a801be00 > > > FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00000000004c8e48 CR3: 00000000a4c08000 CR4: 00000000001506f0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > pcpu_destroy_chunk mm/percpu-vm.c:366 [inline] > > > __pcpu_balance_workfn mm/percpu.c:1982 [inline] > > > pcpu_balance_workfn+0x8b3/0x1310 mm/percpu.c:2069 > > > process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 > > > worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 > > > kthread+0x3b5/0x4a0 kernel/kthread.c:292 > > > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > > Modules linked in: > > > ---[ end trace 6a2e56ec52e1f480 ]--- > > > RIP: 0010:free_vm_area mm/vmalloc.c:3089 [inline] > > > RIP: 0010:free_vm_area mm/vmalloc.c:3085 [inline] > > > RIP: 0010:pcpu_free_vm_areas+0x96/0xc0 mm/vmalloc.c:3432 > > > Code: 75 48 48 8b 2b 48 8d 7d 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 75 2c 48 8b 7d 08 e8 c4 c8 ff ff 48 39 c5 74 a5 e8 ea c3 c9 ff <0f> 0b e8 e3 c3 c9 ff 4c 89 ff 5b 5d 41 5c 41 5d 41 5e 41 5f e9 71 > > > RSP: 0018:ffffc90000d2fba8 EFLAGS: 00010293 > > > RAX: 0000000000000000 RBX: ffff8880a801be00 RCX: 0000000000000000 > > > RDX: ffff8880a95fa300 RSI: ffffffff81aa7c76 RDI: 0000000000000001 > > > RBP: ffff8880a2b38180 R08: 0000000000000000 R09: ffffffff89cfecc3 > > > R10: fffffbfff139fd98 R11: 0000000000000000 R12: 0000000000000000 > > > R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880a801be00 > > > FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00000000004c8e48 CR3: 00000000a4c08000 CR4: 00000000001506f0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > > That is because of below revert: > > > > <snip> > > commit bdbfb1d52d5e576c1d275fd8ab59b677011229e8 > > Author: Ingo Molnar <mingo@xxxxxxxxxx> > > Date: Sun Jun 7 21:12:51 2020 +0200 > > > > Revert "mm/vmalloc: modify struct vmap_area to reduce its size" > > > > This reverts commit 688fcbfc06e4fdfbb7e1d5a942a1460fe6379d2d. > > > > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > > > > Conflicts: > > mm/vmalloc.c > > <snip> > > > > I can check further, but it can be it was not correctly reverted, > > because everything should work just fine even with the revert, > > though i i do not understand a reason of reverting. > > Vlad, how sure are you about this? We also start to trigger this now on > linux-next, but the reverting patch surely looks like doggy without any useful > information in the commit description. > Hello, Andrew, Qian. I am not aware of reason of the revert, though i tried to get through Ingo. I can send out a patch that fixes the revert. Another option to drop the revert, but it is up to Andrew and Ingo. Andrew, could you please comment on? Thank you in advance! -- Vlad Rezki
