bisecting fixing commit since 13d2ce42de8cb98ff952f8de6307f896203854c2 building syzkaller on 97183ed760478c5b970c8c549d99c8147a72e293 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.4.1 20210217 kernel signature: dc611562844998abaa184f8cfb38fbef7afeb3f0118fe699310b653fc0ab5a8c all runs: crashed: divide error in squashfs_readpage testing current HEAD 2965db2e004cf9c92b87c1f559e9812c0ae878c1 testing commit 2965db2e004cf9c92b87c1f559e9812c0ae878c1 with gcc (GCC) 8.4.1 20210217 kernel signature: c36b5a63010ec44fa66794b1d41603de2b6992fcbe397a605221ecf4439c057d all runs: crashed: divide error in squashfs_readpage revisions tested: 2, total time: 22m53.149306176s (build: 16m7.963352021s, test: 6m23.578022256s) the crash still happens on HEAD commit msg: Linux 4.19.188 crash: divide error in squashfs_readpage IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9817 Comm: syz-executor.4 Not tainted 4.19.188-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fill_meta_index fs/squashfs/file.c:256 [inline] RIP: 0010:read_blocklist fs/squashfs/file.c:345 [inline] RIP: 0010:squashfs_readpage+0x8b4/0x2330 fs/squashfs/file.c:482 Code: 8b 47 c8 31 d2 48 63 8d 2c fe ff ff 48 89 85 90 fe ff ff 48 63 85 78 fe ff ff 48 89 cb 48 c1 e1 0b c1 e3 0b 89 9d 60 fe ff ff <48> f7 f1 85 c0 48 89 85 68 fe ff ff 89 85 8c fe ff ff 0f 8e 22 11 ieee80211 phy6: Selected rate control algorithm 'minstrel_ht' RSP: 0018:ffff888096e47578 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 1ffff11013a26fbf RDI: ffff88808110a4c8 RBP: ffff888096e47770 R08: ffffea000205abe0 R09: fffff9400040b57e R10: fffff9400040b57e R11: ffffea000205abf7 R12: ffff88808110a4c0 R13: 00000000000000de R14: 0000000000000099 R15: ffff88808110a4f8 FS: 00007f7af48f1700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000055c009 CR3: 00000000a29b9000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: read_pages+0x2b1/0x510 mm/readahead.c:133 __do_page_cache_readahead+0x353/0x580 mm/readahead.c:211 ra_submit mm/internal.h:66 [inline] ondemand_readahead+0x42b/0xbc0 mm/readahead.c:493 page_cache_sync_readahead mm/readahead.c:528 [inline] page_cache_sync_readahead+0x1d9/0x3c0 mm/readahead.c:510 generic_file_buffered_read mm/filemap.c:2115 [inline] generic_file_read_iter+0xf3d/0x2150 mm/filemap.c:2385 call_read_iter include/linux/fs.h:1815 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x440/0x880 fs/read_write.c:418 vfs_read+0xff/0x300 fs/read_write.c:452 kernel_read+0x90/0x130 fs/read_write.c:431 prepare_binprm+0x5bd/0x810 fs/exec.c:1596 __do_execve_file.isra.12+0xe52/0x1d30 fs/exec.c:1815 do_execveat_common fs/exec.c:1879 [inline] do_execveat+0x18/0x20 fs/exec.c:1907 __do_sys_execveat fs/exec.c:1988 [inline] __se_sys_execveat fs/exec.c:1980 [inline] __x64_sys_execveat+0xe2/0x120 fs/exec.c:1980 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 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:00007f7af48f1188 EFLAGS: 00000246 ORIG_RAX: 0000000000000142 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000005 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffd58b449bf R14: 00007f7af48f1300 R15: 0000000000022000 Modules linked in: ---[ end trace f0c2f831213c352c ]--- IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready RIP: 0010:fill_meta_index fs/squashfs/file.c:256 [inline] RIP: 0010:read_blocklist fs/squashfs/file.c:345 [inline] RIP: 0010:squashfs_readpage+0x8b4/0x2330 fs/squashfs/file.c:482 Code: 8b 47 c8 31 d2 48 63 8d 2c fe ff ff 48 89 85 90 fe ff ff 48 63 85 78 fe ff ff 48 89 cb 48 c1 e1 0b c1 e3 0b 89 9d 60 fe ff ff <48> f7 f1 85 c0 48 89 85 68 fe ff ff 89 85 8c fe ff ff 0f 8e 22 11 wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 ieee80211 phy7: Selected rate control algorithm 'minstrel_ht' wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 RSP: 0018:ffff888096e47578 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready RDX: 0000000000000000 RSI: 1ffff11013a26fbf RDI: ffff88808110a4c8 ieee80211 phy8: Selected rate control algorithm 'minstrel_ht' RBP: ffff888096e47770 R08: ffffea000205abe0 R09: fffff9400040b57e R10: fffff9400040b57e R11: ffffea000205abf7 R12: ffff88808110a4c0 IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready R13: 00000000000000de R14: 0000000000000099 R15: ffff88808110a4f8 FS: 00007f7af48f1700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b958dc88f0 CR3: 00000000a29b9000 CR4: 00000000001406f0 wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50