syzbot


WARNING in ext4_xattr_set_entry (2)

Status: upstream: reported C repro on 2024/04/11 08:11
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+4b03894b6ec5753ddf24@syzkaller.appspotmail.com
First crash: 789d, last: 754d
Cause bisection: failed (error log, bisect log)
  
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
0bb866f4-b3a6-4441-b556-0b654f72220a assessment-security 💥 WARNING in ext4_xattr_set_entry (2) 2026/06/03 00:03 2026/06/03 00:03 2026/06/03 00:32 62fe15281f5011cd203d8845b8767b10e7443aa5 failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/ac4e874c99ebb48f58c3d48f26111f51c5af5fe7" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: drivers/nvme/target/fc.c:151:2: warning: 'counted_by' should not be applied to an array with element of unknown size because 'struct nvmet_fc_fcp_iod' is a struct type with a flexible array member. This will be an error in a future compiler version [-Wbounds-safety-counted-by-elt-type-unknown-size] ld.lld: error: undefined symbol: wcslen * * Restart config... * * * General architecture-dependent options * Kprobes (KPROBES) [N/y/?] n Optimize very unlikely/likely branches (JUMP_LABEL) [Y/n/?] y Static key selftest (STATIC_KEYS_SELFTEST) [N/y/?] n Static call selftest (STATIC_CALL_SELFTEST) [N/y/?] n Enable seccomp to safely execute untrusted bytecode (SECCOMP) [Y/n/?] y Show seccomp filter cache status in /proc/pid/seccomp_cache (SECCOMP_CACHE_DEBUG) [N/y/?] n Link Time Optimization (LTO) > 1. None (LTO_NONE) choice[1]: 1 Use Clang's Control Flow Integrity (CFI) (CFI_CLANG) [N/y/?] (NEW) Error in reading or end of file. Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [28] 28 Number of bits to use for ASLR of mmap base address for compatible applications (ARCH_MMAP_RND_COMPAT_BITS) [8] 8 MMU page size > 1. 4KiB pages (PAGE_SIZE_4KB) choice[1]: 1 Provide system calls for 32-bit time_t (COMPAT_32BIT_TIME) [Y/n/?] y Use a virtually-mapped stack (VMAP_STACK) [Y/n/?] y Support for randomizing kernel stack offset on syscall entry (RANDOMIZE_KSTACK_OFFSET) [Y/n/?] y Default state of kernel stack offset randomization (RANDOMIZE_KSTACK_OFFSET_DEFAULT) [N/y/?] n Locking event counts collection (LOCK_EVENT_COUNTS) [N/y/?] n * * Memory initialization * Initialize kernel stack variables at function entry 1. no automatic stack variable initialization (weakest) (INIT_STACK_NONE) 2. pattern-init everything (strongest) (INIT_STACK_ALL_PATTERN) > 3. zero-init everything (strongest and safest) (INIT_STACK_ALL_ZERO) choice[1-3?]: 3 Enable heap memory zeroing on allocation by default (INIT_ON_ALLOC_DEFAULT_ON) [Y/n/?] y Enable heap memory zeroing on free by default (INIT_ON_FREE_DEFAULT_ON) [N/y/?] n Enable mlocked memory zeroing on free (INIT_MLOCKED_ON_FREE_DEFAULT_ON) [N/y/?] n Enable register zeroing on function exit (ZERO_CALL_USED_REGS) [N/y/?] (NEW) Error in reading or end of file. * * Kernel hardening options * Randomize layout of sensitive kernel structures > 1. Disable structure layout randomization (RANDSTRUCT_NONE) 2. Fully randomize structure layout (RANDSTRUCT_FULL) (NEW) choice[1-2?]: Error in reading or end of file. * * Compile-time checks and compiler options * Debug information 1. Disable debug information (DEBUG_INFO_NONE) 2. Rely on the toolchain's implicit default DWARF version (DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT) > 3. Generate DWARF Version 4 debuginfo (DEBUG_INFO_DWARF4) 4. Generate DWARF Version 5 debuginfo (DEBUG_INFO_DWARF5) choice[1-4?]: 3 Reduce debugging information (DEBUG_INFO_REDUCED) [N/y/?] n Compressed Debug information > 1. Don't compress debug information (DEBUG_INFO_COMPRESSED_NONE) 2. Compress debugging information with zlib (DEBUG_INFO_COMPRESSED_ZLIB) 3. Compress debugging information with zstd (DEBUG_INFO_COMPRESSED_ZSTD) (NEW) choice[1-3?]: Error in reading or end of file. Produce split debuginfo in .dwo files (DEBUG_INFO_SPLIT) [N/y/?] n Generate BTF type information (DEBUG_INFO_BTF) [N/y/?] n Provide GDB scripts for kernel debugging (GDB_SCRIPTS) [N/y/?] n Warn for stack frames larger than (FRAME_WARN) [2048] 2048 Strip assembler-generated symbols during link (STRIP_ASM_SYMS) [N/y/?] n Install uapi headers to usr/include (HEADERS_INSTALL) [N/y/?] n Make section mismatch errors non-fatal (SECTION_MISMATCH_WARN_ONLY) [Y/n/?] y Force all function address 64B aligned (DEBUG_FORCE_FUNCTION_ALIGN_64B) [N/y/?] n Generate vmlinux.map file when linking (VMLINUX_MAP) [N/y
0248d804-f210-4d3f-9d9f-ec5b0084eb9e assessment-security 💥 WARNING in ext4_xattr_set_entry (2) 2026/05/31 20:23 2026/05/31 20:23 2026/05/31 20:52 6b4a844333e83556da95d61d7f207e7ef5cd4bc6 failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/ac4e874c99ebb48f58c3d48f26111f51c5af5fe7" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: drivers/nvme/target/fc.c:151:2: warning: 'counted_by' should not be applied to an array with element of unknown size because 'struct nvmet_fc_fcp_iod' is a struct type with a flexible array member. This will be an error in a future compiler version [-Wbounds-safety-counted-by-elt-type-unknown-size] ld.lld: error: undefined symbol: wcslen * * Restart config... * * * General architecture-dependent options * Kprobes (KPROBES) [N/y/?] n Optimize very unlikely/likely branches (JUMP_LABEL) [Y/n/?] y Static key selftest (STATIC_KEYS_SELFTEST) [N/y/?] n Static call selftest (STATIC_CALL_SELFTEST) [N/y/?] n Enable seccomp to safely execute untrusted bytecode (SECCOMP) [Y/n/?] y Show seccomp filter cache status in /proc/pid/seccomp_cache (SECCOMP_CACHE_DEBUG) [N/y/?] n Link Time Optimization (LTO) > 1. None (LTO_NONE) choice[1]: 1 Use Clang's Control Flow Integrity (CFI) (CFI_CLANG) [N/y/?] (NEW) Error in reading or end of file. Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [28] 28 Number of bits to use for ASLR of mmap base address for compatible applications (ARCH_MMAP_RND_COMPAT_BITS) [8] 8 MMU page size > 1. 4KiB pages (PAGE_SIZE_4KB) choice[1]: 1 Provide system calls for 32-bit time_t (COMPAT_32BIT_TIME) [Y/n/?] y Use a virtually-mapped stack (VMAP_STACK) [Y/n/?] y Support for randomizing kernel stack offset on syscall entry (RANDOMIZE_KSTACK_OFFSET) [Y/n/?] y Default state of kernel stack offset randomization (RANDOMIZE_KSTACK_OFFSET_DEFAULT) [N/y/?] n Locking event counts collection (LOCK_EVENT_COUNTS) [N/y/?] n * * Memory initialization * Initialize kernel stack variables at function entry 1. no automatic stack variable initialization (weakest) (INIT_STACK_NONE) 2. pattern-init everything (strongest) (INIT_STACK_ALL_PATTERN) > 3. zero-init everything (strongest and safest) (INIT_STACK_ALL_ZERO) choice[1-3?]: 3 Enable heap memory zeroing on allocation by default (INIT_ON_ALLOC_DEFAULT_ON) [Y/n/?] y Enable heap memory zeroing on free by default (INIT_ON_FREE_DEFAULT_ON) [N/y/?] n Enable mlocked memory zeroing on free (INIT_MLOCKED_ON_FREE_DEFAULT_ON) [N/y/?] n Enable register zeroing on function exit (ZERO_CALL_USED_REGS) [N/y/?] (NEW) Error in reading or end of file. * * Kernel hardening options * Randomize layout of sensitive kernel structures > 1. Disable structure layout randomization (RANDSTRUCT_NONE) 2. Fully randomize structure layout (RANDSTRUCT_FULL) (NEW) choice[1-2?]: Error in reading or end of file. * * Compile-time checks and compiler options * Debug information 1. Disable debug information (DEBUG_INFO_NONE) 2. Rely on the toolchain's implicit default DWARF version (DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT) > 3. Generate DWARF Version 4 debuginfo (DEBUG_INFO_DWARF4) 4. Generate DWARF Version 5 debuginfo (DEBUG_INFO_DWARF5) choice[1-4?]: 3 Reduce debugging information (DEBUG_INFO_REDUCED) [N/y/?] n Compressed Debug information > 1. Don't compress debug information (DEBUG_INFO_COMPRESSED_NONE) 2. Compress debugging information with zlib (DEBUG_INFO_COMPRESSED_ZLIB) 3. Compress debugging information with zstd (DEBUG_INFO_COMPRESSED_ZSTD) (NEW) choice[1-3?]: Error in reading or end of file. Produce split debuginfo in .dwo files (DEBUG_INFO_SPLIT) [N/y/?] n Generate BTF type information (DEBUG_INFO_BTF) [N/y/?] n Provide GDB scripts for kernel debugging (GDB_SCRIPTS) [N/y/?] n Warn for stack frames larger than (FRAME_WARN) [2048] 2048 Strip assembler-generated symbols during link (STRIP_ASM_SYMS) [N/y/?] n Install uapi headers to usr/include (HEADERS_INSTALL) [N/y/?] n Make section mismatch errors non-fatal (SECTION_MISMATCH_WARN_ONLY) [Y/n/?] y Force all function address 64B aligned (DEBUG_FORCE_FUNCTION_ALIGN_64B) [N/y/?] n Generate vmlinux.map file when linking (VMLINUX_MAP) [N/y
c1d2d7ba-114a-47b9-9cb6-dbd07ad29317 assessment-security 💥 WARNING in ext4_xattr_set_entry (2) 2026/05/15 06:42 2026/05/15 06:42 2026/05/15 06:44 6ccb967e465e832a7bfd7a116ad00d52a0923a5d failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128 From /app/workdir/repo/linux * branch HEAD -> FETCH_HEAD Updating files: 27% (23456/84544) Updating files: 28% (23673/84544) Updating files: 29% (24518/84544) Updating files: 30% (25364/84544) Updating files: 31% (26209/84544) Updating files: 32% (27055/84544) Updating files: 33% (27900/84544) Updating files: 34% (28745/84544) Updating files: 35% (29591/84544) Updating files: 35% (30321/84544) Updating files: 36% (30436/84544) Updating files: 37% (31282/84544) Updating files: 38% (32127/84544) Updating files: 39% (32973/84544) Updating files: 40% (33818/84544) error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_12_0_offset.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_12_0_sh_mask.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_6_0_d.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_6_0_sh_mask.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_8_0_d.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_8_0_enum.h error: unable to write file drivers/gpu/drm/amd/include/asic_reg/dce/dce_8_0_sh_mask.h fatal: cannot create directory at 'drivers/gpu/drm/amd/include/asic_reg/dcn': No space left on device
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] WARNING in ext4_xattr_set_entry (2) 0 (1) 2024/04/11 08:11
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in ext4_xattr_set_entry origin:upstream -1 C error 118 31d 742d 0/3 upstream: reported C repro on 2024/05/26 21:44
upstream WARNING in ext4_xattr_set_entry ext4 -1 C unreliable 7 1920d 2003d 20/29 fixed on 2021/11/10 00:50
linux-4.19 WARNING in ext4_xattr_set_entry -1 C done 12 1918d 2052d 1/1 fixed on 2021/04/07 11:11
linux-4.14 WARNING in ext4_xattr_set_entry -1 C done 19 1920d 2075d 1/1 fixed on 2021/04/07 11:21
Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/04/04 01:10 16m retest repro linux-next report log
2026/03/30 12:36 55m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci error
2026/01/23 21:21 2h01m retest repro linux-next report log
2026/01/19 11:57 22m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/11/14 20:28 35m retest repro linux-next report log
2025/11/10 11:29 24m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/09/05 17:39 40m retest repro linux-next report log
2025/09/01 10:36 18m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/06/27 05:48 24m retest repro linux-next report log
2025/06/22 23:29 23m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log

Sample crash report:
process 'syz-executor225' launched '/dev/fd/4/./file1' with NULL argv: empty string added
EXT4-fs warning (device loop0): ext4_xattr_inode_create:1471: refuse to create EA inode when umounting
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5089 at fs/ext4/xattr.c:1472 ext4_xattr_inode_create fs/ext4/xattr.c:1472 [inline]
WARNING: CPU: 1 PID: 5089 at fs/ext4/xattr.c:1472 ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1590 [inline]
WARNING: CPU: 1 PID: 5089 at fs/ext4/xattr.c:1472 ext4_xattr_set_entry+0x162c/0x4330 fs/ext4/xattr.c:1718
Modules linked in:
CPU: 1 PID: 5089 Comm: syz-executor225 Not tainted 6.9.0-rc3-next-20240409-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:ext4_xattr_inode_create fs/ext4/xattr.c:1472 [inline]
RIP: 0010:ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1590 [inline]
RIP: 0010:ext4_xattr_set_entry+0x162c/0x4330 fs/ext4/xattr.c:1718
Code: 00 00 e8 57 50 2a ff eb 30 e8 50 50 2a ff 4c 89 ff 48 c7 c6 e9 5d b7 8d ba bf 05 00 00 48 c7 c1 00 aa df 8b e8 75 12 fc ff 90 <0f> 0b 90 49 c7 c4 ea ff ff ff 4c 8b 7c 24 70 48 8b 44 24 40 42 80
RSP: 0018:ffffc9000337efa0 EFLAGS: 00010246
RAX: aa755dc17bf17f00 RBX: 0000000000000000 RCX: aa755dc17bf17f00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000337f230 R08: ffffffff8176bb7c R09: 1ffff9200066fd6c
R10: dffffc0000000000 R11: fffff5200066fd6d R12: ffff88807a280cd8
R13: dffffc0000000000 R14: ffffc9000337f150 R15: ffff888060b68000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 0000000060608000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_xattr_block_set+0x6a2/0x3480 fs/ext4/xattr.c:1968
 ext4_xattr_move_to_block fs/ext4/xattr.c:2654 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2729 [inline]
 ext4_expand_extra_isize_ea+0x12d7/0x1cf0 fs/ext4/xattr.c:2821
 __ext4_expand_extra_isize+0x2fb/0x3e0 fs/ext4/inode.c:5789
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5832 [inline]
 __ext4_mark_inode_dirty+0x524/0x880 fs/ext4/inode.c:5910
 ext4_dirty_inode+0xce/0x110 fs/ext4/inode.c:5942
 __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2486
 mark_inode_dirty_sync include/linux/fs.h:2406 [inline]
 iput+0x1fe/0x930 fs/inode.c:1764
 __dentry_kill+0x20d/0x630 fs/dcache.c:603
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1048
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075
 shrink_dcache_parent+0xcb/0x3b0
 do_one_tree+0x23/0xe0 fs/dcache.c:1538
 shrink_dcache_for_umount+0x7d/0x130 fs/dcache.c:1555
 generic_shutdown_super+0x6a/0x2d0 fs/super.c:619
 kill_block_super+0x44/0x90 fs/super.c:1675
 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7323
 deactivate_locked_super+0xc4/0x130 fs/super.c:472
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa1b/0x27e0 kernel/exit.c:878
 do_group_exit+0x207/0x2c0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x72/0x7a
RIP: 0033:0x7f0fe6f95c49
Code: Unable to access opcode bytes at 0x7f0fe6f95c1f.
RSP: 002b:00007ffc0a1edef8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f0fe6f95c49
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 00007f0fe7012390 R08: ffffffffffffffb8 R09: 00007ffc0a1edfd0
R10: 0000000000000381 R11: 0000000000000246 R12: 00007f0fe7012390
R13: 0000000000000000 R14: 00007f0fe7013100 R15: 00007f0fe6f63f20
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/10 13:13 linux-next a053fd3ca5d1 56086b24 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_set_entry
2024/04/10 12:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci fec50db7033e 56086b24 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-gce-arm64 WARNING in ext4_xattr_set_entry
2024/05/14 20:02 upstream a5131c3fdf26 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ext4_xattr_set_entry
2024/05/14 20:02 upstream a5131c3fdf26 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ext4_xattr_set_entry
2024/05/14 20:02 upstream a5131c3fdf26 fdb4c10c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ext4_xattr_set_entry
2024/04/27 19:59 upstream 5eb4573ea63d 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in ext4_xattr_set_entry
2024/04/10 02:32 linux-next a053fd3ca5d1 56086b24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_set_entry
2024/05/12 23:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci fda5695d692c 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in ext4_xattr_set_entry
2024/04/10 11:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci fec50db7033e 56086b24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in ext4_xattr_set_entry
* Struck through repros no longer work on HEAD.