bisecting fixing commit since 7ac3a1c1ae5152e1d18cf6df5b6c3c9847535e78 building syzkaller on 858ea628800647d5e5b68b11441e42b8ef5652c1 testing commit 7ac3a1c1ae5152e1d18cf6df5b6c3c9847535e78 with gcc (GCC) 10.2.1 20210217 kernel signature: 8184e56227c4ea0764285fe1526bca86ea2646814defd004eacc5dbff31eaeb4 run #0: crashed: kernel BUG in __page_mapcount run #1: OK run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK run #10: OK run #11: OK run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK reproducer seems to be flaky testing current HEAD b7050b242430f3170e0b57f5f55136e44cb8dc66 testing commit b7050b242430f3170e0b57f5f55136e44cb8dc66 with gcc (GCC) 10.2.1 20210217 kernel signature: 38ed87a6ab91987199925d34dded79c8532c148449b7ed305f466549f4768fc5 run #0: crashed: kernel BUG in __page_mapcount run #1: OK run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK run #10: OK run #11: OK run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK Reproducer flagged being flaky revisions tested: 2, total time: 32m48.905130689s (build: 14m1.573329319s, test: 18m21.821281877s) the crash still happens on HEAD commit msg: Merge tag 'pinctrl-v5.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl crash: kernel BUG in __page_mapcount get_signal+0x3b2/0x1c60 kernel/signal.c:2850 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x180/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57 entry_SYSCALL_64_after_hwframe+0x44/0xae ------------[ cut here ]------------ kernel BUG at include/linux/page-flags.h:686! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 15618 Comm: syz-executor.2 Not tainted 5.13.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:PageDoubleMap include/linux/page-flags.h:686 [inline] RIP: 0010:__page_mapcount+0x1f7/0x270 mm/util.c:728 Code: 5b 44 89 e0 5d 41 5c 41 5d c3 48 c7 c6 e0 28 b4 88 48 89 ef e8 aa bf 03 00 0f 0b 48 c7 c6 40 29 b4 88 48 89 ef e8 99 bf 03 00 <0f> 0b 48 c7 c6 80 29 b4 88 4c 89 ef e8 88 bf 03 00 0f 0b 4c 89 e7 RSP: 0018:ffffc900038e75e8 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 00000000ffffea00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff88fe15e0 RDI: ffff88801282a9fa RBP: ffffea0001a38d40 R08: 0000000000000029 R09: ffff8880b9e2fec7 R10: ffffed10173c5fd8 R11: 535f7972746e6520 R12: 00000000ffffffff R13: ffffea0001a38d94 R14: dffffc0000000000 R15: ffffea0001a38000 FS: 00007fe88578f700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002c72848 CR3: 0000000016b68000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: page_mapcount include/linux/mm.h:873 [inline] smaps_account+0x20a/0x7e0 fs/proc/task_mmu.c:467 smaps_pte_entry fs/proc/task_mmu.c:533 [inline] smaps_pte_range+0x3fc/0xd80 fs/proc/task_mmu.c:596 walk_pmd_range mm/pagewalk.c:89 [inline] walk_pud_range mm/pagewalk.c:160 [inline] walk_p4d_range mm/pagewalk.c:193 [inline] walk_pgd_range mm/pagewalk.c:229 [inline] __walk_page_range+0xa3c/0x1710 mm/pagewalk.c:331 walk_page_vma+0x216/0x2d0 mm/pagewalk.c:482 smap_gather_stats fs/proc/task_mmu.c:739 [inline] show_smaps_rollup+0x297/0x7e0 fs/proc/task_mmu.c:872 seq_read_iter+0x3fe/0x1000 fs/seq_file.c:227 seq_read+0x311/0x4e0 fs/seq_file.c:159 do_loop_readv_writev fs/read_write.c:761 [inline] do_loop_readv_writev fs/read_write.c:748 [inline] do_iter_read+0x382/0x620 fs/read_write.c:803 vfs_readv+0xc3/0x130 fs/read_write.c:921 do_preadv fs/read_write.c:1013 [inline] __do_sys_preadv fs/read_write.c:1063 [inline] __se_sys_preadv fs/read_write.c:1058 [inline] __x64_sys_preadv+0x1d7/0x290 fs/read_write.c:1058 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe88578f188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000000001 RSI: 0000000020000780 RDI: 0000000000000004 RBP: 00000000004bfcb9 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe9d699b0f R14: 00007fe88578f300 R15: 0000000000022000 Modules linked in: ---[ end trace 6c1e883efbd36173 ]--- RIP: 0010:PageDoubleMap include/linux/page-flags.h:686 [inline] RIP: 0010:__page_mapcount+0x1f7/0x270 mm/util.c:728 Code: 5b 44 89 e0 5d 41 5c 41 5d c3 48 c7 c6 e0 28 b4 88 48 89 ef e8 aa bf 03 00 0f 0b 48 c7 c6 40 29 b4 88 48 89 ef e8 99 bf 03 00 <0f> 0b 48 c7 c6 80 29 b4 88 4c 89 ef e8 88 bf 03 00 0f 0b 4c 89 e7 RSP: 0018:ffffc900038e75e8 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 00000000ffffea00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff88fe15e0 RDI: ffff88801282a9fa RBP: ffffea0001a38d40 R08: 0000000000000029 R09: ffff8880b9e2fec7 R10: ffffed10173c5fd8 R11: 535f7972746e6520 R12: 00000000ffffffff R13: ffffea0001a38d94 R14: dffffc0000000000 R15: ffffea0001a38000 FS: 00007fe88578f700(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002c72848 CR3: 0000000016b68000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400