| Message ID | 20220823133755.314697-2-liujian56@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3f8ef65af927db247418d4e1db49164d7a158fc5 |
| Delegated to: | BPF |
| Headers | show |
| Series | If the sock is dead, do not access sock's sk_wq in sk_stream_wait_memory | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Series has a cover letter |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 342 this patch: 342 |
| netdev/cc_maintainers | warning | 2 maintainers not CCed: weiwan@google.com netdev@vger.kernel.org |
| netdev/build_clang | success | Errors and warnings before: 5 this patch: 5 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/check_selftest | success | No net selftest shell script |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 342 this patch: 342 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 9 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
| bpf/vmtest-bpf-next-VM_Test-17 | success | Logs for test_verifier on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-4 | success | Logs for llvm-toolchain |
| bpf/vmtest-bpf-next-VM_Test-5 | success | Logs for set-matrix |
| bpf/vmtest-bpf-next-VM_Test-2 | success | Logs for build for x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-3 | success | Logs for build for x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-16 | success | Logs for test_verifier on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-13 | success | Logs for test_progs_no_alu32 on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-10 | success | Logs for test_progs on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-14 | success | Logs for test_progs_no_alu32 on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-7 | success | Logs for test_maps on x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-8 | success | Logs for test_maps on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-11 | success | Logs for test_progs on x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-9 | success | Logs for test_progs on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-12 | success | Logs for test_progs_no_alu32 on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-15 | success | Logs for test_verifier on s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-6 | success | Logs for test_maps on s390x with gcc |
| bpf/vmtest-bpf-next-PR | fail | PR summary |
| bpf/vmtest-bpf-next-VM_Test-1 | success | Logs for llvm-toolchain |
Liu Jian wrote: > Fix the below NULL pointer dereference: > > [ 14.471200] Call Trace: > [ 14.471562] <TASK> > [ 14.471882] lock_acquire+0x245/0x2e0 > [ 14.472416] ? remove_wait_queue+0x12/0x50 > [ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50 > [ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50 > [ 14.474318] ? remove_wait_queue+0x12/0x50 > [ 14.474907] remove_wait_queue+0x12/0x50 > [ 14.475480] sk_stream_wait_memory+0x20d/0x340 > [ 14.476127] ? do_wait_intr_irq+0x80/0x80 > [ 14.476704] do_tcp_sendpages+0x287/0x600 > [ 14.477283] tcp_bpf_push+0xab/0x260 > [ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500 > [ 14.478461] ? __local_bh_enable_ip+0x77/0xe0 > [ 14.479096] tcp_bpf_send_verdict+0x105/0x470 > [ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0 > [ 14.480311] sock_sendmsg+0x2d/0x40 > [ 14.480822] ____sys_sendmsg+0x1b4/0x1c0 > [ 14.481390] ? copy_msghdr_from_user+0x62/0x80 > [ 14.482048] ___sys_sendmsg+0x78/0xb0 > [ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150 > [ 14.483215] ? __do_fault+0x2a/0x1a0 > [ 14.483738] ? do_fault+0x15e/0x5d0 > [ 14.484246] ? __handle_mm_fault+0x56b/0x1040 > [ 14.484874] ? lock_is_held_type+0xdf/0x130 > [ 14.485474] ? find_held_lock+0x2d/0x90 > [ 14.486046] ? __sys_sendmsg+0x41/0x70 > [ 14.486587] __sys_sendmsg+0x41/0x70 > [ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350 > [ 14.487822] do_syscall_64+0x34/0x80 > [ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The test scene as following flow: > thread1 thread2 > ----------- --------------- > tcp_bpf_sendmsg > tcp_bpf_send_verdict > tcp_bpf_sendmsg_redir sock_close > tcp_bpf_push_locked __sock_release > tcp_bpf_push //inet_release > do_tcp_sendpages sock->ops->release > sk_stream_wait_memory // tcp_close > sk_wait_event sk->sk_prot->close > release_sock(__sk); > *** > > lock_sock(sk); > __tcp_close > sock_orphan(sk) > sk->sk_wq = NULL > release_sock > **** > lock_sock(__sk); > remove_wait_queue(sk_sleep(sk), &wait); > sk_sleep(sk) > //NULL pointer dereference > &rcu_dereference_raw(sk->sk_wq)->wait > > While waiting for memory in thread1, the socket is released with its wait > queue because thread2 has closed it. This caused by tcp_bpf_send_verdict > didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1. > > We should check if SOCK_DEAD flag is set on wakeup in > sk_stream_wait_memory, before accessing the wait queue. > > Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> > Signed-off-by: Liu Jian <liujian56@huawei.com> > --- This LGTM but would be great if Eric could ACK as well from TCP side. Acked-by: John Fastabend <john.fastabend@gmail.com>
diff --git a/net/core/stream.c b/net/core/stream.c index ccc083cdef23..1105057ce00a 100644 --- a/net/core/stream.c +++ b/net/core/stream.c @@ -159,7 +159,8 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) *timeo_p = current_timeo; } out: - remove_wait_queue(sk_sleep(sk), &wait); + if (!sock_flag(sk, SOCK_DEAD)) + remove_wait_queue(sk_sleep(sk), &wait); return err; do_error:
Fix the below NULL pointer dereference: [ 14.471200] Call Trace: [ 14.471562] <TASK> [ 14.471882] lock_acquire+0x245/0x2e0 [ 14.472416] ? remove_wait_queue+0x12/0x50 [ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50 [ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50 [ 14.474318] ? remove_wait_queue+0x12/0x50 [ 14.474907] remove_wait_queue+0x12/0x50 [ 14.475480] sk_stream_wait_memory+0x20d/0x340 [ 14.476127] ? do_wait_intr_irq+0x80/0x80 [ 14.476704] do_tcp_sendpages+0x287/0x600 [ 14.477283] tcp_bpf_push+0xab/0x260 [ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500 [ 14.478461] ? __local_bh_enable_ip+0x77/0xe0 [ 14.479096] tcp_bpf_send_verdict+0x105/0x470 [ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0 [ 14.480311] sock_sendmsg+0x2d/0x40 [ 14.480822] ____sys_sendmsg+0x1b4/0x1c0 [ 14.481390] ? copy_msghdr_from_user+0x62/0x80 [ 14.482048] ___sys_sendmsg+0x78/0xb0 [ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150 [ 14.483215] ? __do_fault+0x2a/0x1a0 [ 14.483738] ? do_fault+0x15e/0x5d0 [ 14.484246] ? __handle_mm_fault+0x56b/0x1040 [ 14.484874] ? lock_is_held_type+0xdf/0x130 [ 14.485474] ? find_held_lock+0x2d/0x90 [ 14.486046] ? __sys_sendmsg+0x41/0x70 [ 14.486587] __sys_sendmsg+0x41/0x70 [ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350 [ 14.487822] do_syscall_64+0x34/0x80 [ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd The test scene as following flow: thread1 thread2 ----------- --------------- tcp_bpf_sendmsg tcp_bpf_send_verdict tcp_bpf_sendmsg_redir sock_close tcp_bpf_push_locked __sock_release tcp_bpf_push //inet_release do_tcp_sendpages sock->ops->release sk_stream_wait_memory // tcp_close sk_wait_event sk->sk_prot->close release_sock(__sk); *** lock_sock(sk); __tcp_close sock_orphan(sk) sk->sk_wq = NULL release_sock **** lock_sock(__sk); remove_wait_queue(sk_sleep(sk), &wait); sk_sleep(sk) //NULL pointer dereference &rcu_dereference_raw(sk->sk_wq)->wait While waiting for memory in thread1, the socket is released with its wait queue because thread2 has closed it. This caused by tcp_bpf_send_verdict didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1. We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory, before accessing the wait queue. Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Liu Jian <liujian56@huawei.com> --- v1->v2: As Jakub's suggested, check sock's DEAD flag before accessing the wait queue. net/core/stream.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)