user/sven/linux.git/kernel, branch v4.20

fork,memcg: fix crash in free_thread_stack on memcg charge fail

2018-12-21T22:51:18Z

Commit 9b6f7e163cd0 ("mm: rework memcg kernel stack accounting") will result in fork failing if allocating a kernel stack for a task in dup_task_struct exceeds the kernel memory allowance for that cgroup. Unfortunately, it also results in a crash. This is due to the code jumping to free_stack and calling free_thread_stack when the memcg kernel stack charge fails, but without tsk->stack pointing at the freshly allocated stack. This in turn results in the vfree_atomic in free_thread_stack oopsing with a backtrace like this: #5 [ffffc900244efc88] die at ffffffff8101f0ab #6 [ffffc900244efcb8] do_general_protection at ffffffff8101cb86 #7 [ffffc900244efce0] general_protection at ffffffff818ff082 [exception RIP: llist_add_batch+7] RIP: ffffffff8150d487 RSP: ffffc900244efd98 RFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88085ef55980 RCX: 0000000000000000 RDX: ffff88085ef55980 RSI: 343834343531203a RDI: 343834343531203a RBP: ffffc900244efd98 R8: 0000000000000001 R9: ffff8808578c3600 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88029f6c21c0 R13: 0000000000000286 R14: ffff880147759b00 R15: 0000000000000000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #8 [ffffc900244efda0] vfree_atomic at ffffffff811df2c7 #9 [ffffc900244efdb8] copy_process at ffffffff81086e37 #10 [ffffc900244efe98] _do_fork at ffffffff810884e0 #11 [ffffc900244eff10] sys_vfork at ffffffff810887ff #12 [ffffc900244eff20] do_syscall_64 at ffffffff81002a43 RIP: 000000000049b948 RSP: 00007ffcdb307830 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: 0000000000896030 RCX: 000000000049b948 RDX: 0000000000000000 RSI: 00007ffcdb307790 RDI: 00000000005d7421 RBP: 000000000067370f R8: 00007ffcdb3077b0 R9: 000000000001ed00 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000040 R13: 000000000000000f R14: 0000000000000000 R15: 000000000088d018 ORIG_RAX: 000000000000003a CS: 0033 SS: 002b The simplest fix is to assign tsk->stack right where it is allocated. Link: http://lkml.kernel.org/r/20181214231726.7ee4843c@imladris.surriel.com Fixes: 9b6f7e163cd0 ("mm: rework memcg kernel stack accounting") Signed-off-by: Rik van Riel Acked-by: Roman Gushchin Acked-by: Michal Hocko Cc: Shakeel Butt Cc: Johannes Weiner Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-12-21T18:51:54Z

Pull timer fix from Ingo Molnar: "Fix a division by zero crash in the posix-timers code" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: posix-timers: Fix division by zero bug

Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-12-21T18:11:51Z

Pull futex fix from Ingo Molnar: "A single fix for a robust futexes race between sys_exit() and sys_futex_lock_pi()" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Cure exit race

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-12-20T07:34:33Z

Pull networking fixes from David Miller: 1) Off by one in netlink parsing of mac802154_hwsim, from Alexander Aring. 2) nf_tables RCU usage fix from Taehee Yoo. 3) Flow dissector needs nhoff and thoff clamping, from Stanislav Fomichev. 4) Missing sin6_flowinfo initialization in SCTP, from Xin Long. 5) Spectrev1 in ipmr and ip6mr, from Gustavo A. R. Silva. 6) Fix r8169 crash when DEBUG_SHIRQ is enabled, from Heiner Kallweit. 7) Fix SKB leak in rtlwifi, from Larry Finger. 8) Fix state pruning in bpf verifier, from Jakub Kicinski. 9) Don't handle completely duplicate fragments as overlapping, from Michal Kubecek. 10) Fix memory corruption with macb and 64-bit DMA, from Anssi Hannula. 11) Fix TCP fallback socket release in smc, from Myungho Jung. 12) gro_cells_destroy needs to napi_disable, from Lorenzo Bianconi. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (130 commits) rds: Fix warning. neighbor: NTF_PROXY is a valid ndm_flag for a dump request net: mvpp2: fix the phylink mode validation net/sched: cls_flower: Remove old entries from rhashtable net/tls: allocate tls context using GFP_ATOMIC iptunnel: make TUNNEL_FLAGS available in uapi gro_cell: add napi_disable in gro_cells_destroy lan743x: Remove MAC Reset from initialization net/mlx5e: Remove the false indication of software timestamping support net/mlx5: Typo fix in del_sw_hw_rule net/mlx5e: RX, Fix wrong early return in receive queue poll ipv6: explicitly initialize udp6_addr in udp_sock_create6() bnxt_en: Fix ethtool self-test loopback. net/rds: remove user triggered WARN_ON in rds_sendmsg net/rds: fix warn in rds_message_alloc_sgs ath10k: skip sending quiet mode cmd for WCN3990 mac80211: free skb fraglist before freeing the skb nl80211: fix memory leak if validate_pae_over_nl80211() fails net/smc: fix TCP fallback socket release vxge: ensure data0 is initialized in when fetching firmware version information ...

futex: Cure exit race

2018-12-18T22:13:15Z

Stefan reported, that the glibc tst-robustpi4 test case fails occasionally. That case creates the following race between sys_exit() and sys_futex_lock_pi(): CPU0 CPU1 sys_exit() sys_futex() do_exit() futex_lock_pi() exit_signals(tsk) No waiters: tsk->flags |= PF_EXITING; *uaddr == 0x00000PID mm_release(tsk) Set waiter bit exit_robust_list(tsk) { *uaddr = 0x80000PID; Set owner died attach_to_pi_owner() { *uaddr = 0xC0000000; tsk = get_task(PID); } if (!tsk->flags & PF_EXITING) { ... attach(); tsk->flags |= PF_EXITPIDONE; } else { if (!(tsk->flags & PF_EXITPIDONE)) return -EAGAIN; return -ESRCH; <--- FAIL } ESRCH is returned all the way to user space, which triggers the glibc test case assert. Returning ESRCH unconditionally is wrong here because the user space value has been changed by the exiting task to 0xC0000000, i.e. the FUTEX_OWNER_DIED bit is set and the futex PID value has been cleared. This is a valid state and the kernel has to handle it, i.e. taking the futex. Cure it by rereading the user space value when PF_EXITING and PF_EXITPIDONE is set in the task which 'owns' the futex. If the value has changed, let the kernel retry the operation, which includes all regular sanity checks and correctly handles the FUTEX_OWNER_DIED case. If it hasn't changed, then return ESRCH as there is no way to distinguish this case from malfunctioning user space. This happens when the exiting task did not have a robust list, the robust list was corrupted or the user space value in the futex was simply bogus. Reported-by: Stefan Liebler Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: Heiko Carstens Cc: Darren Hart Cc: Ingo Molnar Cc: Sasha Levin Cc: stable@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=200467 Link: https://lkml.kernel.org/r/20181210152311.986181245@linutronix.de

dma-direct: do not include SME mask in the DMA supported check

2018-12-17T17:02:11Z

The dma_direct_supported() function intends to check the DMA mask against specific values. However, the phys_to_dma() function includes the SME encryption mask, which defeats the intended purpose of the check. This results in drivers that support less than 48-bit DMA (SME encryption mask is bit 47) from being able to set the DMA mask successfully when SME is active, which results in the driver failing to initialize. Change the function used to check the mask from phys_to_dma() to __phys_to_dma() so that the SME encryption mask is not part of the check. Fixes: c1d0af1a1d5d ("kernel/dma/direct: take DMA offset into account in dma_direct_supported") Signed-off-by: Tom Lendacky Signed-off-by: Christoph Hellwig

posix-timers: Fix division by zero bug

2018-12-17T16:35:45Z

The signal delivery path of posix-timers can try to rearm the timer even if the interval is zero. That's handled for the common case (hrtimer) but not for alarm timers. In that case the forwarding function raises a division by zero exception. The handling for hrtimer based posix timers is wrong because it marks the timer as active despite the fact that it is stopped. Move the check from common_hrtimer_rearm() to posixtimer_rearm() to cure both issues. Reported-by: syzbot+9d38bedac9cc77b8ad5e@syzkaller.appspotmail.com Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Linus Torvalds Cc: Peter Zijlstra Cc: sboyd@kernel.org Cc: stable@vger.kernel.org Cc: syzkaller-bugs@googlegroups.com Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1812171328050.1880@nanos.tec.linutronix.de Signed-off-by: Ingo Molnar

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2018-12-15T18:58:32Z

Alexei Starovoitov says: ==================== pull-request: bpf 2018-12-15 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) fix liveness propagation of callee saved registers, from Jakub. 2) fix overflow in bpf_jit_limit knob, from Daniel. 3) bpf_flow_dissector api fix, from Stanislav. 4) bpf_perf_event api fix on powerpc, from Sandipan. ==================== Signed-off-by: David S. Miller

bpf: verifier: make sure callees don't prune with caller differences

2018-12-13T18:35:40Z

Currently for liveness and state pruning the register parentage chains don't include states of the callee. This makes some sense as the callee can't access those registers. However, this means that READs done after the callee returns will not propagate into the states of the callee. Callee will then perform pruning disregarding differences in caller state. Example: 0: (85) call bpf_user_rnd_u32 1: (b7) r8 = 0 2: (55) if r0 != 0x0 goto pc+1 3: (b7) r8 = 1 4: (bf) r1 = r8 5: (85) call pc+4 6: (15) if r8 == 0x1 goto pc+1 7: (05) *(u64 *)(r9 - 8) = r3 8: (b7) r0 = 0 9: (95) exit 10: (15) if r1 == 0x0 goto pc+0 11: (95) exit Here we acquire unknown state with call to get_random() [1]. Then we store this random state in r8 (either 0 or 1) [1 - 3], and make a call on line 5. Callee does nothing but a trivial conditional jump (to create a pruning point). Upon return caller checks the state of r8 and either performs an unsafe read or not. Verifier will first explore the path with r8 == 1, creating a pruning point at [11]. The parentage chain for r8 will include only callers states so once verifier reaches [6] it will mark liveness only on states in the caller, and not [11]. Now when verifier walks the paths with r8 == 0 it will reach [11] and since REG_LIVE_READ on r8 was not propagated there it will prune the walk entirely (stop walking the entire program, not just the callee). Since [6] was never walked with r8 == 0, [7] will be considered dead and replaced with "goto -1" causing hang at runtime. This patch weaves the callee's explored states onto the callers parentage chain. Rough parentage for r8 would have looked like this before: [0] [1] [2] [3] [4] [5] [10] [11] [6] [7] | | ,---|----. | | | sl0: sl0: / sl0: \ sl0: sl0: sl0: fr0: r8 <-- fr0: r8<+--fr0: r8 `fr0: r8 ,fr0: r8<-fr0: r8 \ fr1: r8 <- fr1: r8 / \__________________/ after: [0] [1] [2] [3] [4] [5] [10] [11] [6] [7] | | | | | | sl0: sl0: sl0: sl0: sl0: sl0: fr0: r8 <-- fr0: r8 <- fr0: r8 <- fr0: r8 <-fr0: r8<-fr0: r8 fr1: r8 <- fr1: r8 Now the mark from instruction 6 will travel through callees states. Note that we don't have to connect r0 because its overwritten by callees state on return and r1 - r5 because those are not alive any more once a call is made. v2: - don't connect the callees registers twice (Alexei: suggestion & code) - add more details to the comment (Ed & Alexei) v1: don't unnecessarily link caller saved regs (Jiong) Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)") Reported-by: David Beckett Signed-off-by: Jakub Kicinski Reviewed-by: Jiong Wang Reviewed-by: Edward Cree Signed-off-by: Alexei Starovoitov

Merge tag 'trace-v4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2018-12-13T02:15:29Z

Pull tracing fixes from Steven Rostedt: "While running various ftrace tests on new development code, the kmemleak detector found some allocations that were not freed correctly. This fixes a couple of leaks in the event trigger code as well as in adding function trace filters in trace instances" * tag 'trace-v4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix memory leak of instance function hash filters tracing: Fix memory leak in set_trigger_filter() tracing: Fix memory leak in create_filter()