syzbot ci has tested the following series
[v1] bpf: Fix unintended eviction when updating lru hash maps https://lore.kernel.org/all/20251202153032.10118-1-leon.hwang@linux.dev * [PATCH bpf-next 1/3] bpf: Avoid unintended eviction when updating lru_hash maps * [PATCH bpf-next 2/3] bpf: Avoid unintended eviction when updating lru_percpu_hash maps * [PATCH bpf-next 3/3] selftests/bpf: Add tests to verify no unintended eviction when updating lru hash maps
and found the following issue: general protection fault in bpf_lru_push_free
Full report is available here: https://ci.syzbot.org/series/64db9547-852d-4c56-a3a1-3d18f254330c
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general protection fault in bpf_lru_push_free
tree: bpf-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git base: 5262cb23393f7e86a64d1a45eeaa8a6f99f03d10 arch: amd64 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 config: https://ci.syzbot.org/builds/702a7a8c-4385-4089-a777-8b47155f8794/config C repro: https://ci.syzbot.org/findings/0cffd810-925f-42f4-88d2-8d21195f341e/c_repro syz repro: https://ci.syzbot.org/findings/0cffd810-925f-42f4-88d2-8d21195f341e/syz_repr...
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 0 UID: 0 PID: 5953 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:bpf_percpu_lru_push_free kernel/bpf/bpf_lru_list.c:539 [inline] RIP: 0010:bpf_lru_push_free+0x6e/0xbb0 kernel/bpf/bpf_lru_list.c:551 Code: 01 0f 85 e4 00 00 00 4c 89 f0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 f7 e8 c0 82 42 00 4d 8b 3e 4c 8d 73 10 4c 89 f0 48 c1 e8 03 <0f> b6 04 28 84 c0 0f 85 5b 09 00 00 45 0f b7 36 bf 08 00 00 00 44 RSP: 0018:ffffc900046d7b48 EFLAGS: 00010202 RAX: 0000000000000004 RBX: 0000000000000010 RCX: ffff888112941d00 RDX: 0000000000000000 RSI: 0000000000000010 RDI: ffff888117c02300 RBP: dffffc0000000000 R08: ffffffff8f7cee77 R09: 1ffffffff1ef9dce R10: dffffc0000000000 R11: fffffbfff1ef9dcf R12: 0000000000000002 R13: 00000000fffffffe R14: 0000000000000020 R15: 0000607d55cf6a80 FS: 000055555edc7500(0000) GS:ffff88818eb38000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ed63fff CR3: 000000010bca0000 CR4: 00000000000006f0 Call Trace: <TASK> htab_lru_push_free kernel/bpf/hashtab.c:1183 [inline] htab_lru_map_update_elem+0x33e/0xa90 kernel/bpf/hashtab.c:1266 bpf_map_update_value+0x751/0x920 kernel/bpf/syscall.c:294 map_update_elem+0x355/0x4b0 kernel/bpf/syscall.c:1817 __sys_bpf+0x619/0x860 kernel/bpf/syscall.c:6150 __do_sys_bpf kernel/bpf/syscall.c:6272 [inline] __se_sys_bpf kernel/bpf/syscall.c:6270 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6270 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe41118f7c9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffcd4179988 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fe4113e5fa0 RCX: 00007fe41118f7c9 RDX: 0000000000000020 RSI: 0000200000000800 RDI: 0000000000000002 RBP: 00007fe4111f297f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe4113e5fa0 R14: 00007fe4113e5fa0 R15: 0000000000000003 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:bpf_percpu_lru_push_free kernel/bpf/bpf_lru_list.c:539 [inline] RIP: 0010:bpf_lru_push_free+0x6e/0xbb0 kernel/bpf/bpf_lru_list.c:551 Code: 01 0f 85 e4 00 00 00 4c 89 f0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 f7 e8 c0 82 42 00 4d 8b 3e 4c 8d 73 10 4c 89 f0 48 c1 e8 03 <0f> b6 04 28 84 c0 0f 85 5b 09 00 00 45 0f b7 36 bf 08 00 00 00 44 RSP: 0018:ffffc900046d7b48 EFLAGS: 00010202 RAX: 0000000000000004 RBX: 0000000000000010 RCX: ffff888112941d00 RDX: 0000000000000000 RSI: 0000000000000010 RDI: ffff888117c02300 RBP: dffffc0000000000 R08: ffffffff8f7cee77 R09: 1ffffffff1ef9dce R10: dffffc0000000000 R11: fffffbfff1ef9dcf R12: 0000000000000002 R13: 00000000fffffffe R14: 0000000000000020 R15: 0000607d55cf6a80 FS: 000055555edc7500(0000) GS:ffff88818eb38000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ed63fff CR3: 000000010bca0000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 01 0f add %ecx,(%rdi) 2: 85 e4 test %esp,%esp 4: 00 00 add %al,(%rax) 6: 00 4c 89 f0 add %cl,-0x10(%rcx,%rcx,4) a: 48 c1 e8 03 shr $0x3,%rax e: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) 12: 74 08 je 0x1c 14: 4c 89 f7 mov %r14,%rdi 17: e8 c0 82 42 00 call 0x4282dc 1c: 4d 8b 3e mov (%r14),%r15 1f: 4c 8d 73 10 lea 0x10(%rbx),%r14 23: 4c 89 f0 mov %r14,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 0f b6 04 28 movzbl (%rax,%rbp,1),%eax <-- trapping instruction 2e: 84 c0 test %al,%al 30: 0f 85 5b 09 00 00 jne 0x991 36: 45 0f b7 36 movzwl (%r14),%r14d 3a: bf 08 00 00 00 mov $0x8,%edi 3f: 44 rex.R
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If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com
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