bisecting fixing commit since 6794862a16ef41f753abd75c03a152836e4c8028 building syzkaller on 5a5826a14e99564bdd4de163d3ac368056e5d992 testing commit 6794862a16ef41f753abd75c03a152836e4c8028 with gcc (GCC) 8.1.0 kernel signature: fac0338fce360292237889e14a364732d864641b all runs: crashed: KASAN: wild-memory-access Read in insert_char testing current HEAD 040a3c33623ba4bd11588ab0820281b854a3ffaf testing commit 040a3c33623ba4bd11588ab0820281b854a3ffaf with gcc (GCC) 8.1.0 kernel signature: 50370b093ee645c0a1cb7e584de5936b0010fe35 all runs: crashed: KASAN: wild-memory-access Read in insert_char revisions tested: 2, total time: 20m21.994085746s (build: 12m46.295150655s, test: 6m54.443284473s) the crash still happens on HEAD commit msg: Merge tag 'iommu-fixes-v5.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu crash: KASAN: wild-memory-access Read in insert_char ================================================================== BUG: KASAN: wild-memory-access in memmove include/linux/string.h:395 [inline] BUG: KASAN: wild-memory-access in scr_memmovew include/linux/vt_buffer.h:68 [inline] BUG: KASAN: wild-memory-access in insert_char+0x1e2/0x3e0 drivers/tty/vt/vt.c:839 Read of size 212 at addr 00000000ffffff3a by task syz-executor.5/8009 CPU: 1 PID: 8009 Comm: syz-executor.5 Not tainted 5.5.0-rc5-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 __kasan_report.cold.11+0x5/0x3a mm/kasan/report.c:510 kasan_report+0x12/0x20 mm/kasan/common.c:639 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x153/0x1d0 mm/kasan/generic.c:192 memmove+0x23/0x50 mm/kasan/common.c:116 memmove include/linux/string.h:395 [inline] scr_memmovew include/linux/vt_buffer.h:68 [inline] insert_char+0x1e2/0x3e0 drivers/tty/vt/vt.c:839 csi_at drivers/tty/vt/vt.c:1964 [inline] do_con_trol+0x5742/0x63d0 drivers/tty/vt/vt.c:2431 do_con_write.part.25+0xab6/0x1ad0 drivers/tty/vt/vt.c:2797 do_con_write drivers/tty/vt/vt.c:2565 [inline] con_write+0x1f/0x80 drivers/tty/vt/vt.c:3135 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x494/0xfa0 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x371/0x7d0 drivers/tty/tty_io.c:1046 __vfs_write+0x5e/0x110 fs/read_write.c:494 vfs_write+0x18a/0x520 fs/read_write.c:558 ksys_write+0x105/0x220 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __ia32_sys_write+0x6c/0xa0 fs/read_write.c:620 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x235/0xb68 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f71a09 Code: 00 00 00 89 d3 eb dd b8 80 96 98 00 eb c7 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f7f6d0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020000000 RDX: 0000000000000078 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ==================================================================