ci2 starts bisection 2026-08-03 03:45:00.969388075 +0000 UTC m=+177694.940401366
bisecting fixing commit since 7f4b368e04101e5f8788b55d139505e6cb5e0b67
building syzkaller on 9cd3beaadf14b3a22d15fd97a0bf081ee41ebe01
ensuring issue is reproducible on original commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67

testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 0f208658b2ae7b3d5e7cfbe030efa7b3534274a7f3c0dec0f5c71c6ad1251afb
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: KASAN: use-after-free Read in ext4_find_extent
run #6: crashed: KASAN: use-after-free Read in __crc32c_le_base
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
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: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
check whether we can drop unnecessary instrumentation
disabling configs for [hang memleak ubsan bug_or_warning locking atomic_sleep], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: aed2549e449396e83931e038790d1a977eced8ebfd3c102e6c2a4dbe5fd7eab4
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: invalid opcode in ext4_ext_insert_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: KASAN: use-after-free Read in __crc32c_le_base
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
the bug reproduces without the instrumentation
disabling configs for [memleak ubsan bug_or_warning locking atomic_sleep hang], they are not needed
kconfig minimization: base=4921 full=6218 leaves diff=256
split chunks (needed=false): <256>
split chunk #0 of len 256 into 5 parts
testing without sub-chunk 1/5
disabling configs for [ubsan bug_or_warning locking atomic_sleep hang memleak], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: d1bdb1cfb35b4235f0dccb1c0adcb9a1905a59d752a4b44812d0f24898760104
all runs: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 643c4668f51486c059bf208e843d33a9b9bf854ba1c62d6b3de25270803a62a2
all runs: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: ce73eb389a3bb16e8e32cb5a137a6132ba12125f3b283f9b7d8a9e55b9e0fc44
all runs: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: ea8995c280cf6a1f725122e2d2d50c25a5858781abbc1456fd2762da0cc843c0
all runs: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [hang memleak ubsan bug_or_warning locking atomic_sleep], they are not needed
testing commit 7f4b368e04101e5f8788b55d139505e6cb5e0b67 gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
failed building 7f4b368e04101e5f8788b55d139505e6cb5e0b67: net/socket.c:1188:(.text+0x6d1a): undefined reference to `wext_handle_ioctl'
net/socket.c:3389:(.text+0x7314): undefined reference to `compat_wext_handle_ioctl'
net/core/net-procfs.c:343:(.text+0x33b): undefined reference to `wext_proc_exit'
net/core/net-procfs.c:327:(.text+0x4e2): undefined reference to `wext_proc_init'
minimized to 48 configs; suspects: [HID_ZEROPLUS 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 USB_SERIAL_FTDI_SIO 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 USB_XHCI_PCI_RENESAS WLAN WLAN_VENDOR_ATH WLAN_VENDOR_ATMEL WLAN_VENDOR_BROADCOM WLAN_VENDOR_INTERSIL WLAN_VENDOR_MARVELL WLAN_VENDOR_MEDIATEK WLAN_VENDOR_MICROCHIP WLAN_VENDOR_RALINK WLAN_VENDOR_REALTEK WLAN_VENDOR_RSI WLAN_VENDOR_ZYDAS ZEROPLUS_FF]
disabling configs for [atomic_sleep hang memleak ubsan bug_or_warning locking], they are not needed
testing current HEAD 61d896ee2a8005c4e9d9da24421ba554601421be
testing commit 61d896ee2a8005c4e9d9da24421ba554601421be gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 6669a387bdb2d8939c0a5882cf4bae4cf25cee066106b14e26dd2ab86956c808
all runs: crashed: KASAN: use-after-free Read in ext4_find_extent
representative crash: KASAN: use-after-free Read in ext4_find_extent, types: [KASAN-USE-AFTER-FREE-READ]
crash still not fixed/happens on the oldest tested release
revisions tested: 7, total time: 2h8m2.920220658s (build: 38m56.61334312s, test: 1h1m23.995885849s)
crash still not fixed or there were kernel test errors
commit msg: Revert "hdlc_ppp: sync per-proto timers before freeing hdlc state"
crash: KASAN: use-after-free Read in ext4_find_extent
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xb93/0xc70 fs/ext4/extents.c:946
Read of size 4 at addr ffff8881233a4148 by task kworker/u4:4/356

CPU: 0 PID: 356 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: writeback wb_workfn (flush-7:2)
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x38/0x49 lib/dump_stack.c:106
 print_address_description.constprop.0+0x24/0x160 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report.cold+0x82/0xdb mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
 ext4_find_extent+0xb93/0xc70 fs/ext4/extents.c:946
 ext4_ext_map_blocks+0x16e/0x52a0 fs/ext4/extents.c:4197
 ext4_map_blocks+0x58d/0x1430 fs/ext4/inode.c:676
 mpage_map_one_extent fs/ext4/inode.c:2423 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2476 [inline]
 ext4_writepages+0x135a/0x2a80 fs/ext4/inode.c:2844
 do_writepages+0x18c/0x770 mm/page-writeback.c:2388
 __writeback_single_inode+0x6e/0x730 fs/fs-writeback.c:1657
 writeback_sb_inodes+0x4ab/0xe80 fs/fs-writeback.c:1940
 wb_writeback+0x154/0x6b0 fs/fs-writeback.c:2116
 wb_do_writeback fs/fs-writeback.c:2263 [inline]
 wb_workfn+0x247/0xe20 fs/fs-writeback.c:2304
 process_one_work+0x62c/0xec0 kernel/workqueue.c:2328
 worker_thread+0x48e/0xdb0 kernel/workqueue.c:2475
 kthread+0x324/0x3e0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

The buggy address belongs to the page:
page:ffffea00048ce900 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1233a4
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea00048ce8c8 ffffea00048ce848 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 288, ts 28442231210, free_ts 31049237296
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook mm/page_alloc.c:2607 [inline]
 prep_new_page+0x1a2/0x310 mm/page_alloc.c:2613
 get_page_from_freelist+0x1ce2/0x30a0 mm/page_alloc.c:4487
 __alloc_pages+0x300/0x2d60 mm/page_alloc.c:5824
 __alloc_pages_node include/linux/gfp.h:595 [inline]
 alloc_pages_node include/linux/gfp.h:609 [inline]
 alloc_pages include/linux/gfp.h:622 [inline]
 do_anonymous_page mm/memory.c:4072 [inline]
 handle_pte_fault+0xc54/0x31c0 mm/memory.c:4921
 __handle_mm_fault+0x4ea/0x1480 mm/memory.c:5219
 do_handle_mm_fault+0x33b/0x690 mm/memory.c:5345
 do_user_addr_fault+0x726/0x1120 arch/x86/mm/fault.c:1323
 handle_page_fault arch/x86/mm/fault.c:1507 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1560
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare+0x263/0x660 mm/page_alloc.c:1546
 free_unref_page_prepare mm/page_alloc.c:3536 [inline]
 free_unref_page_list+0x1e3/0xcd0 mm/page_alloc.c:3673
 release_pages+0x382/0x12d0 mm/swap.c:1015
 free_pages_and_swap_cache+0x5d/0x80 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu+0xbe/0x590 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1528 [inline]
 zap_pmd_range mm/memory.c:1577 [inline]
 zap_pud_range mm/memory.c:1606 [inline]
 zap_p4d_range mm/memory.c:1627 [inline]
 unmap_page_range+0x117c/0x1bf0 mm/memory.c:1648
 unmap_single_vma mm/memory.c:1693 [inline]
 unmap_vmas+0x1dc/0x3a0 mm/memory.c:1725
 exit_mmap+0x1f8/0x840 mm/mmap.c:3245
 __mmput+0x70/0x3a0 kernel/fork.c:1185
 mmput kernel/fork.c:1208 [inline]
 mmput+0x35/0xf0 kernel/fork.c:1202
 exit_mm kernel/exit.c:555 [inline]
 do_exit+0x90f/0x2540 kernel/exit.c:877
 do_group_exit+0xe6/0x290 kernel/exit.c:1004
 get_signal+0x236/0x1e10 kernel/signal.c:2908
 arch_do_signal_or_restart+0x2bc/0x1bb0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x91/0xe0 kernel/entry/common.c:178
 exit_to_user_mode_prepare kernel/entry/common.c:214 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x58/0x70 kernel/entry/common.c:307

Memory state around the buggy address:
 ffff8881233a4000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881233a4080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881233a4100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881233a4180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881233a4200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 11245524728104540515 in block_group 0
EXT4-fs error (device loop2): ext4_map_blocks:742: inode #18: block 112589990684262: comm kworker/u4:4: lblock 0 mapped to illegal pblock 112589990684262 (length 16)
EXT4-fs (loop2): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 16 with error 117
EXT4-fs (loop2): This should not happen!! Data will be lost

EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 4443660483033309957 in block_group 0
EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 17855033580110492690 in block_group 0
EXT4-fs error (device loop2): ext4_map_blocks:742: inode #18: block 2400886718464: comm kworker/u4:4: lblock 0 mapped to illegal pblock 2400886718464 (length 16)
EXT4-fs (loop2): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 16 with error 117
EXT4-fs (loop2): This should not happen!! Data will be lost

EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 11933451037919455597 in block_group 0
EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 17055609068891539410 in block_group 0
EXT4-fs error (device loop2): __ext4_get_inode_loc:4364: comm kworker/u4:4: Invalid inode table block 17543987724278180362 in block_group 0