ci2 starts bisection 2025-06-30 20:17:39.281870472 +0000 UTC m=+11217.845423242
bisecting fixing commit since db710ea87c32d5f806ffaaccbf98ecd3108314e4
building syzkaller on 3d2f584ddab119da50e8a8d26765aa98d3b33c02
ensuring issue is reproducible on original commit db710ea87c32d5f806ffaaccbf98ecd3108314e4

testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: 2d0be58a3e739b1ecc5a14471d3ce1dfd7db57fdd441d5ac12ba030bdeff3843
run #0: crashed: KASAN: use-after-free Read in ext4_find_extent
run #1: crashed: kernel BUG in ext4_writepages
run #2: crashed: kernel BUG in ext4_writepages
run #3: crashed: kernel BUG in ext4_writepages
run #4: crashed: KASAN: use-after-free Read in ext4_find_extent
run #5: crashed: kernel BUG in ext4_writepages
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: KASAN: use-after-free Read in ext4_find_extent
run #8: crashed: kernel BUG in ext4_writepages
run #9: crashed: kernel BUG in ext4_writepages
run #10: crashed: KASAN: use-after-free Read in ext4_find_extent
run #11: crashed: KASAN: use-after-free Read in ext4_find_extent
run #12: crashed: KASAN: use-after-free Read in ext4_find_extent
run #13: crashed: KASAN: use-after-free Read in ext4_find_extent
run #14: crashed: KASAN: use-after-free Read in ext4_find_extent
run #15: crashed: KASAN: use-after-free Read in ext4_find_extent
run #16: crashed: KASAN: use-after-free Read in ext4_find_extent
run #17: crashed: KASAN: use-after-free Read in ext4_find_extent
run #18: crashed: KASAN: use-after-free Read in ext4_find_extent
run #19: crashed: kernel BUG in ext4_writepages
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN BUG]
check whether we can drop unnecessary instrumentation
disabling configs for [HANG LEAK UBSAN LOCKDEP ATOMIC_SLEEP], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: 52d0feb2c993d76b3f8a0056344dcf20343503066a63d197b13fcc383a92169d
run #0: crashed: KASAN: use-after-free Read in ext4_find_extent
run #1: crashed: KASAN: use-after-free Read in ext4_find_extent
run #2: crashed: kernel BUG in ext4_writepages
run #3: crashed: KASAN: use-after-free Read in ext4_find_extent
run #4: crashed: KASAN: use-after-free Read in ext4_find_extent
run #5: crashed: kernel BUG in ext4_writepages
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: KASAN: use-after-free Read in ext4_find_extent
run #8: crashed: KASAN: use-after-free Read in ext4_find_extent
run #9: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN]
the bug reproduces without the instrumentation
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
kconfig minimization: base=5186 full=6555 leaves diff=264
split chunks (needed=false): <264>
split chunk #0 of len 264 into 5 parts
testing without sub-chunk 1/5
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: e035ccfd6746fac327da48b7867fcd15afa7a62c03d076788ca0a194f46ceea0
run #0: crashed: KASAN: use-after-free Read in ext4_find_extent
run #1: crashed: kernel BUG in ext4_writepages
run #2: crashed: KASAN: use-after-free Read in ext4_find_extent
run #3: crashed: KASAN: use-after-free Read in ext4_find_extent
run #4: crashed: kernel BUG in ext4_writepages
run #5: crashed: KASAN: use-after-free Read in ext4_find_extent
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: KASAN: use-after-free Read in ext4_find_extent
run #8: crashed: KASAN: use-after-free Read in ext4_find_extent
run #9: crashed: kernel BUG in ext4_writepages
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN BUG]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: c9ebfabe6b5eebf2d8bdf4aefda124f076853d5ed0ff4dc64c1d6356e2f3334c
run #0: crashed: KASAN: use-after-free Read in ext4_find_extent
run #1: crashed: KASAN: use-after-free Read in ext4_find_extent
run #2: crashed: KASAN: use-after-free Read in ext4_find_extent
run #3: crashed: KASAN: use-after-free Read in ext4_find_extent
run #4: crashed: KASAN: use-after-free Read in ext4_find_extent
run #5: crashed: kernel BUG in ext4_writepages
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: KASAN: use-after-free Read in ext4_find_extent
run #8: crashed: KASAN: use-after-free Read in ext4_find_extent
run #9: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [UBSAN LOCKDEP ATOMIC_SLEEP HANG LEAK], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: b82bb27772192e79fa46b9cf20c981b82370c008139211dd9540444b5f9fa078
run #0: crashed: KASAN: use-after-free Read in ext4_find_extent
run #1: crashed: KASAN: use-after-free Read in ext4_find_extent
run #2: crashed: KASAN: use-after-free Read in ext4_find_extent
run #3: crashed: kernel BUG in ext4_writepages
run #4: crashed: KASAN: use-after-free Read in ext4_find_extent
run #5: crashed: KASAN: use-after-free Read in ext4_find_extent
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: kernel BUG in ext4_writepages
run #8: crashed: KASAN: use-after-free Read in ext4_find_extent
run #9: crashed: kernel BUG in ext4_writepages
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN BUG]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: fd9df26bb924dedd327ff83f824a642f114d248f6183d77fe02fcfcba83b5805
run #0: crashed: kernel BUG in ext4_writepages
run #1: crashed: KASAN: use-after-free Read in ext4_find_extent
run #2: crashed: kernel BUG in ext4_writepages
run #3: crashed: KASAN: use-after-free Read in ext4_find_extent
run #4: crashed: kernel BUG in ext4_writepages
run #5: crashed: KASAN: use-after-free Read in ext4_find_extent
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: kernel BUG in ext4_writepages
run #8: crashed: kernel BUG in ext4_writepages
run #9: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: kernel BUG in ext4_writepages, types: [BUG KASAN]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [LEAK UBSAN LOCKDEP ATOMIC_SLEEP HANG], they are not needed
testing commit db710ea87c32d5f806ffaaccbf98ecd3108314e4 gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
failed building db710ea87c32d5f806ffaaccbf98ecd3108314e4: ld.lld: error: undefined symbol: wext_proc_init
ld.lld: error: undefined symbol: wext_proc_exit
ld.lld: error: undefined symbol: wext_handle_ioctl
ld.lld: error: undefined symbol: compat_wext_handle_ioctl
minimized to 52 configs; suspects: [HID_ZEROPLUS USB_NET_CDC_MBIM USB_NET_CDC_SUBSET USB_NET_CDC_SUBSET_ENABLE USB_NET_DM9601 USB_NET_GL620A USB_NET_MCS7830 USB_NET_NET1080 USB_NET_PLUSB USB_NET_RNDIS_HOST USB_NET_SMSC75XX USB_NET_SMSC95XX USB_NET_SR9700 USB_NET_SR9800 USB_NET_ZAURUS USB_OHCI_HCD USB_OHCI_HCD_PCI USB_OHCI_HCD_PLATFORM USB_OTG USB_OTG_FSM USB_PRINTER USB_SERIAL_GENERIC USB_SERIAL_PL2303 USB_STORAGE_ALAUDA USB_STORAGE_CYPRESS_ATACB USB_STORAGE_DATAFAB USB_STORAGE_FREECOM USB_STORAGE_ISD200 USB_STORAGE_JUMPSHOT USB_STORAGE_KARMA USB_STORAGE_ONETOUCH USB_STORAGE_SDDR09 USB_STORAGE_SDDR55 USB_STORAGE_USBAT USB_TRANCEVIBRATOR USB_U_AUDIO USB_U_ETHER USB_U_SERIAL USB_WDM V4L2_ASYNC V4L2_FWNODE VIDEO_CAMERA_SENSOR WLAN WLAN_VENDOR_ATH WLAN_VENDOR_ATMEL WLAN_VENDOR_BROADCOM WLAN_VENDOR_INTERSIL WLAN_VENDOR_MARVELL WLAN_VENDOR_MEDIATEK WLAN_VENDOR_MICROCHIP WLAN_VENDOR_PURELIFI WLAN_VENDOR_RALINK WLAN_VENDOR_REALTEK WLAN_VENDOR_RSI WLAN_VENDOR_SILABS WLAN_VENDOR_ZYDAS ZEROPLUS_FF]
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing current HEAD a71768f6d03683713928eb0294bdf4e81266e9dd
testing commit a71768f6d03683713928eb0294bdf4e81266e9dd gcc
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
kernel signature: a038cb89902c48a9ac2b4ea772d5987068e3920ca8128112e58b23d1b3bfa848
run #0: crashed: kernel BUG in ext4_writepages
run #1: crashed: KASAN: use-after-free Read in ext4_find_extent
run #2: crashed: KASAN: use-after-free Read in ext4_find_extent
run #3: crashed: KASAN: use-after-free Read in ext4_find_extent
run #4: crashed: KASAN: use-after-free Read in ext4_find_extent
run #5: crashed: KASAN: use-after-free Read in ext4_find_extent
run #6: crashed: KASAN: use-after-free Read in ext4_find_extent
run #7: crashed: KASAN: use-after-free Read in ext4_find_extent
run #8: crashed: KASAN: use-after-free Read in ext4_find_extent
run #9: crashed: kernel BUG in ext4_writepages
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN]
crash still not fixed/happens on the oldest tested release
revisions tested: 7, total time: 1h8m41.892661948s (build: 33m46.653668983s, test: 31m21.307984501s)
crash still not fixed or there were kernel test errors
commit msg: ANDROID: GKI: Add symbol list for Nothing
crash: KASAN: use-after-free Read in ext4_find_extent
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbe6/0xda0 fs/ext4/extents.c:953
Read of size 4 at addr ffff88812be51d18 by task kworker/u4:0/8

CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-7:2)
Call Trace:
 <TASK>
 __dump_stack+0x19/0x1c lib/dump_stack.c:88
 dump_stack_lvl+0xa3/0xec lib/dump_stack.c:106
 print_address_description+0x71/0x210 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:427
 kasan_report+0x122/0x150 mm/kasan/report.c:531
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350
 ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
 ext4_find_extent+0xbe6/0xda0 fs/ext4/extents.c:953
 ext4_ext_map_blocks+0x1cd/0x5240 fs/ext4/extents.c:4165
 ext4_map_blocks+0x756/0x1680 fs/ext4/inode.c:679
 mpage_map_one_extent fs/ext4/inode.c:2435 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2488 [inline]
 ext4_writepages+0x10f7/0x24c0 fs/ext4/inode.c:2856
 do_writepages+0x335/0x530 mm/page-writeback.c:2494
 __writeback_single_inode+0x9d/0x790 fs/fs-writeback.c:1612
 writeback_sb_inodes+0x76a/0x11a0 fs/fs-writeback.c:1903
 wb_writeback+0x37c/0x7c0 fs/fs-writeback.c:2079
 wb_do_writeback fs/fs-writeback.c:2226 [inline]
 wb_workfn+0x347/0xb30 fs/fs-writeback.c:2266
 process_one_work+0x70a/0xbd0 kernel/workqueue.c:2299
 worker_thread+0x8c0/0xf60 kernel/workqueue.c:2446
 kthread+0x245/0x2d0 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004af9440 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12be51
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004af9488 ffffea0004af9408 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff88812be51c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812be51c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88812be51d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88812be51d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812be51e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2447!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8 Comm: kworker/u4:0 Tainted: G    B              6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-7:2)
RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2447 [inline]
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2488 [inline]
RIP: 0010:ext4_writepages+0x2332/0x24c0 fs/ext4/inode.c:2856
Code: e8 23 5f d3 ff e9 d2 e4 ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 14 e5 ff ff 4c 89 f7 e8 05 5f d3 ff e9 07 e5 ff ff 0f 0b <0f> 0b 65 8b 05 d5 9d 39 7e 89 c3 c1 e8 06 48 8d 3c c5 e8 91 af 85
RSP: 0018:ffffc90000087140 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000042b RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc900000874b0 R08: dffffc0000000000 R09: ffffed1022361302
R10: ffffed1022361302 R11: 1ffff11022361301 R12: 1ffff1102236130e
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888111b09848
FS:  0000000000000000(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000000540f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_writepages+0x335/0x530 mm/page-writeback.c:2494
 __writeback_single_inode+0x9d/0x790 fs/fs-writeback.c:1612
 writeback_sb_inodes+0x76a/0x11a0 fs/fs-writeback.c:1903
 wb_writeback+0x37c/0x7c0 fs/fs-writeback.c:2079
 wb_do_writeback fs/fs-writeback.c:2226 [inline]
 wb_workfn+0x347/0xb30 fs/fs-writeback.c:2266
 process_one_work+0x70a/0xbd0 kernel/workqueue.c:2299
 worker_thread+0x8c0/0xf60 kernel/workqueue.c:2446
 kthread+0x245/0x2d0 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2447 [inline]
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2488 [inline]
RIP: 0010:ext4_writepages+0x2332/0x24c0 fs/ext4/inode.c:2856
Code: e8 23 5f d3 ff e9 d2 e4 ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 14 e5 ff ff 4c 89 f7 e8 05 5f d3 ff e9 07 e5 ff ff 0f 0b <0f> 0b 65 8b 05 d5 9d 39 7e 89 c3 c1 e8 06 48 8d 3c c5 e8 91 af 85
RSP: 0018:ffffc90000087140 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000042b RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc900000874b0 R08: dffffc0000000000 R09: ffffed1022361302
R10: ffffed1022361302 R11: 1ffff11022361301 R12: 1ffff1102236130e
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888111b09848
FS:  0000000000000000(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000010dcbb000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400