bisecting fixing commit since 9455d25f4e3b3d009fa1b810862e5b06229530e4 building syzkaller on 1508f45368a309a3b1196a342b3d64ce7be4cc43 testing commit 9455d25f4e3b3d009fa1b810862e5b06229530e4 with gcc (GCC) 8.1.0 kernel signature: 097a744cc8f7df1b1277516e825faed0b290cdfea381741d833f0fef5fde0d41 all runs: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer testing current HEAD 5cf9ad0e6b164a90581a59609dbf5bda3f5a089c testing commit 5cf9ad0e6b164a90581a59609dbf5bda3f5a089c with gcc (GCC) 8.1.0 kernel signature: 26ea42195362922846fdbc764f751d2838d2a031f25cfdf1521c12ab46d21bac run #0: boot failed: failed to get create image operation operation-1580073230672-59d1177a2228c-6e76234c-806962af: googleapi: Error 503: Internal error. Please try again or contact Google Support. (Code: '-4276358615107997416'), backendError run #1: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #2: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #3: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #4: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #5: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #6: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #7: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #8: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer run #9: crashed: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer revisions tested: 2, total time: 20m34.301489976s (build: 12m54.244383944s, test: 7m1.830169788s) the crash still happens on HEAD commit msg: Merge tag 'io_uring-5.5-2020-01-26' of git://git.kernel.dk/linux-block crash: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer ================================================================== BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] BUG: KASAN: global-out-of-bounds in fb_pad_aligned_buffer+0xd3/0x130 drivers/video/fbdev/core/fbmem.c:115 Read of size 1 at addr ffffffff87cec2dc by task syz-executor.0/8421 CPU: 0 PID: 8421 Comm: syz-executor.0 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x12d/0x187 lib/dump_stack.c:118 print_address_description.constprop.8.cold.10+0x58/0x31d mm/kasan/report.c:374 __kasan_report.cold.11+0x1b/0x3a mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] fb_pad_aligned_buffer+0xd3/0x130 drivers/video/fbdev/core/fbmem.c:115 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:99 [inline] bit_putcs+0x81e/0xf00 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x313/0x530 drivers/video/fbdev/core/fbcon.c:1353 do_update_region+0x30c/0x640 drivers/tty/vt/vt.c:677 redraw_screen+0x54d/0x720 drivers/tty/vt/vt.c:1011 fbcon_do_set_font+0x631/0x940 drivers/video/fbdev/core/fbcon.c:2605 fbcon_copy_font+0x116/0x1a0 drivers/video/fbdev/core/fbcon.c:2620 con_font_copy drivers/tty/vt/vt.c:4594 [inline] con_font_op+0x228/0x1210 drivers/tty/vt/vt.c:4609 vt_ioctl+0xa2c/0x21f0 drivers/tty/vt/vt_ioctl.c:965 tty_ioctl+0x45b/0x12f0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x196/0x1190 fs/ioctl.c:732 ksys_ioctl+0x62/0x90 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:754 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a6f9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2383f1ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a6f9 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000004 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2383f1b6d4 R13: 00000000004c382b R14: 00000000004d8d78 R15: 00000000ffffffff The buggy address belongs to the variable: oid_index+0x93c/0xb80 Memory state around the buggy address: ffffffff87cec180: fa fa fa fa 00 01 fa fa fa fa fa fa 04 fa fa fa ffffffff87cec200: fa fa fa fa 04 fa fa fa fa fa fa fa 07 fa fa fa >ffffffff87cec280: fa fa fa fa 04 fa fa fa fa fa fa fa 05 fa fa fa ^ ffffffff87cec300: fa fa fa fa 01 fa fa fa fa fa fa fa 00 00 02 fa ffffffff87cec380: fa fa fa fa 00 00 00 05 fa fa fa fa 00 00 00 fa ==================================================================