bisecting fixing commit since a844dc4c544291470aa69edbe2434b040794e269 building syzkaller on 1508f45368a309a3b1196a342b3d64ce7be4cc43 testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0 kernel signature: 7b084422a0e176ab4ad383a230c436e5a7ddabe0e0540fdbe28ec4f8386b2efc all runs: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer testing current HEAD 050272a0423e68207fd2367831ae610680129062 testing commit 050272a0423e68207fd2367831ae610680129062 with gcc (GCC) 8.1.0 kernel signature: 5f93758dde2e963255c532b6dfd17dfe3517f34f12345b46e5661c52faef016b all runs: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer revisions tested: 2, total time: 24m15.242806188s (build: 17m22.7200217s, test: 5m57.508267911s) the crash still happens on HEAD commit msg: Linux 4.14.177 crash: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready ================================================================== BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: global-out-of-bounds in fb_pad_aligned_buffer+0xd3/0x130 drivers/video/fbdev/core/fbmem.c:122 Read of size 1 at addr ffffffff87060d36 by task syz-executor.0/7289 CPU: 0 PID: 7289 Comm: syz-executor.0 Not tainted 4.14.177-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xf7/0x13b lib/dump_stack.c:58 print_address_description.cold.7+0x135/0x1c9 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.8+0x11a/0x2d3 mm/kasan/report.c:409 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] fb_pad_aligned_buffer+0xd3/0x130 drivers/video/fbdev/core/fbmem.c:122 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:99 [inline] bit_putcs+0x7fd/0xee0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x2fb/0x5b0 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x304/0x630 drivers/tty/vt/vt.c:373 redraw_screen+0x50d/0x7f0 drivers/tty/vt/vt.c:705 fbcon_do_set_font+0x656/0xa20 drivers/video/fbdev/core/fbcon.c:2564 fbcon_copy_font+0x116/0x1a0 drivers/video/fbdev/core/fbcon.c:2579 con_font_copy drivers/tty/vt/vt.c:4238 [inline] con_font_op+0x219/0x1020 drivers/tty/vt/vt.c:4253 vt_ioctl+0x9da/0x21f0 drivers/tty/vt/vt_ioctl.c:980 tty_ioctl+0x434/0x1260 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a6f9 RSP: 002b:00007f9b3acb4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a6f9 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9b3acb56d4 R13: 00000000004c382b R14: 00000000004d8d78 R15: 00000000ffffffff The buggy address belongs to the variable: oid_index+0x76/0x9a0 Memory state around the buggy address: ffffffff87060c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffff87060c80: 00 00 00 05 fa fa fa fa 00 00 00 00 00 00 00 00 >ffffffff87060d00: 00 00 00 00 00 00 06 fa fa fa fa fa 00 02 fa fa ^ ffffffff87060d80: fa fa fa fa 00 01 fa fa fa fa fa fa 00 00 02 fa ffffffff87060e00: fa fa fa fa 00 03 fa fa fa fa fa fa 07 fa fa fa ================================================================== IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready 8021q: adding VLAN 0 to HW filter on device batadv0 IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bond: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bond: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready