The linux-next commit "mm/rmap.c: reuse mergeable anon_vma as parent when fork" [1] causes a crash on s390 while compiling some C code. Reverted it fixes the issue. [1] https://lore.kernel.org/lkml/20191004160632.30251-1-richardw.yang@xxxxxxxxxxxxxxx/ 00: [ 330.681233] vma 0000000049a08008 start 000003ff8ee7f000 end 000003ff8eee4 00: 000 00: [ 330.681233] next 000000004f272008 prev 0000000065c84230 mm 0000000037d1c1 00: 00 00: [ 330.681233] prot 711 anon_vma 000000001f4e4a80 vm_ops 0000000000000000 00: [ 330.681233] pgoff 3ff8ee7f file 0000000000000000 private_data 00000000000 00: 00000 00: [ 330.681233] flags: 0x8100073(read|write|mayread|maywrite|mayexec|account| 00: softdirty) 00: [ 330.681344] ------------[ cut here ]------------ 00: [ 330.681357] kernel BUG at include/linux/rmap.h:159! 00: [ 330.681442] illegal operation: 0001 ilc:1 [#1] SMP DEBUG_PAGEALLOC 00: [ 330.681460] Modules linked in: ip_tables x_tables xfs dasd_fba_mod dasd_e 00: ckd_mod dm_mirror dm_region_hash dm_log dm_mod 00: [ 330.681502] CPU: 0 PID: 7651 Comm: cc1 Not tainted 5.4.0-rc2-next-2019100 00: 9+ #4 00: [ 330.681516] Hardware name: IBM 2964 N96 400 (z/VM 6.4.0) 00: [ 330.681530] Krnl PSW : 0704c00180000000 00000000531d9cac (__vma_adjust+0x 00: cf4/0xf30) 00: [ 330.681561] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 00: RI:0 EA:3 00: [ 330.681579] Krnl GPRS: 0000000000000001 0000030000000000 0000000000000146 00: 000000006cc03da4 00: [ 330.681595] 0000030000000000 000000005304378c 00000000513de008 00: 0000000000000000 00: [ 330.681611] 0000000049a08008 0000000049a08080 0000000000000000 00: 000000005a178438 00: [ 330.681627] 0000000053bae3b0 0000000037d1c100 00000000531d9ca8 00: 00000000235ef880 01: HCPGSP2629I The virtual machine is placed in CP mode due to a SIGP stop from CPU 01. 01: HCPGSP2629I The virtual machine is placed in CP mode due to a SIGP stop from CPU 00. 00: [ 330.681668] Krnl Code: 00000000531d9c9c: fae0b9040028 ap 2308 00: (15,%r11),40(1,%r0) 00: [ 330.681668] 00000000531d9ca2: c0e5ffff145f brasl %r14 00: ,531bc560 00: [ 330.681668] #00000000531d9ca8: a7f40001 brc 15,5 00: 31d9caa 00: [ 330.681668] >00000000531d9cac: c020005f1a5a larl %r2, 00: 53dbd160 00: [ 330.681668] 00000000531d9cb2: c0e50015ec2b brasl %r14 00: ,53497508 00: [ 330.681668] 00000000531d9cb8: e320f0d80004 lg %r2, 00: 216(%r15) 00: [ 330.681668] 00000000531d9cbe: c0e500040de1 brasl %r14 00: ,5325b880 00: [ 330.681668] 00000000531d9cc4: 4120d038 la %r2, 00: 56(%r13) 00: [ 330.682579] Call Trace: 00: [ 330.682665] ([<00000000531d9ca8>] __vma_adjust+0xcf0/0xf30) 00: [ 330.682684] [<00000000531da4f0>] vma_merge+0x608/0x6b8 00: [ 330.682699] [<00000000531de3b8>] mmap_region+0x1e0/0x9b0 00: [ 330.682713] [<00000000531defec>] do_mmap+0x464/0x650 00: [ 330.682730] [<00000000531930ba>] vm_mmap_pgoff+0x132/0x1c0 00: [ 330.682745] [<00000000531da7b4>] ksys_mmap_pgoff+0xd4/0x458 00: [ 330.682761] [<00000000531dac54>] __s390x_sys_old_mmap+0xdc/0x108 00: [ 330.682779] [<00000000537dcdd0>] system_call+0xd8/0x2b4 00: [ 330.682791] INFO: lockdep is turned off. 00: [ 330.682801] Last Breaking-Event-Address: 00: [ 330.682815] [<00000000531d9ca8>] __vma_adjust+0xcf0/0xf30 00: [ 330.682833] Kernel panic - not syncing: Fatal exception: panic_on_oops
