user/sven/linux.git/kernel, branch v4.15.11

locking/locktorture: Fix num reader/writer corner cases

2018-03-19T08:10:00Z

[ Upstream commit 2ce77d16db4240dd2e422fc0a5c26d3e2ec03446 ] Things can explode for locktorture if the user does combinations of nwriters_stress=0 nreaders_stress=0. Fix this by not assuming we always want to torture writer threads. Reported-by: Jeremy Linton Signed-off-by: Davidlohr Bueso Signed-off-by: Paul E. McKenney Reviewed-by: Jeremy Linton Tested-by: Jeremy Linton Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bpf: fix stack state printing in verifier log

2018-03-19T08:09:54Z

[ Upstream commit 12a3cc8424fe1237aaeb982dec4f0914ddd22f3e ] fix incorrect stack state prints in print_verifier_state() Fixes: 638f5b90d460 ("bpf: reduce verifier memory consumption") Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

sched: Stop resched_cpu() from sending IPIs to offline CPUs

2018-03-19T08:09:51Z

[ Upstream commit a0982dfa03efca6c239c52cabebcea4afb93ea6b ] The rcutorture test suite occasionally provokes a splat due to invoking resched_cpu() on an offline CPU: WARNING: CPU: 2 PID: 8 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40 Modules linked in: CPU: 2 PID: 8 Comm: rcu_preempt Not tainted 4.14.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 task: ffff902ede9daf00 task.stack: ffff96c50010c000 RIP: 0010:native_smp_send_reschedule+0x37/0x40 RSP: 0018:ffff96c50010fdb8 EFLAGS: 00010096 RAX: 000000000000002e RBX: ffff902edaab4680 RCX: 0000000000000003 RDX: 0000000080000003 RSI: 0000000000000000 RDI: 00000000ffffffff RBP: ffff96c50010fdb8 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 00000000299f36ae R12: 0000000000000001 R13: ffffffff9de64240 R14: 0000000000000001 R15: ffffffff9de64240 FS: 0000000000000000(0000) GS:ffff902edfc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000f7d4c642 CR3: 000000001e0e2000 CR4: 00000000000006e0 Call Trace: resched_curr+0x8f/0x1c0 resched_cpu+0x2c/0x40 rcu_implicit_dynticks_qs+0x152/0x220 force_qs_rnp+0x147/0x1d0 ? sync_rcu_exp_select_cpus+0x450/0x450 rcu_gp_kthread+0x5a9/0x950 kthread+0x142/0x180 ? force_qs_rnp+0x1d0/0x1d0 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x27/0x40 Code: 14 01 0f 92 c0 84 c0 74 14 48 8b 05 14 4f f4 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 38 89 ca 9d e8 e5 56 08 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 52 9e 37 02 85 c0 75 38 55 48 ---[ end trace 26df9e5df4bba4ac ]--- This splat cannot be generated by expedited grace periods because they always invoke resched_cpu() on the current CPU, which is good because expedited grace periods require that resched_cpu() unconditionally succeed. However, other parts of RCU can tolerate resched_cpu() acting as a no-op, at least as long as it doesn't happen too often. This commit therefore makes resched_cpu() invoke resched_curr() only if the CPU is either online or is the current CPU. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

sched: Stop switched_to_rt() from sending IPIs to offline CPUs

2018-03-19T08:09:51Z

[ Upstream commit 2fe2582649aa2355f79acddb86bd4d6c5363eb63 ] The rcutorture test suite occasionally provokes a splat due to invoking rt_mutex_lock() which needs to boost the priority of a task currently sitting on a runqueue that belongs to an offline CPU: WARNING: CPU: 0 PID: 12 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40 Modules linked in: CPU: 0 PID: 12 Comm: rcub/7 Not tainted 4.14.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 task: ffff9ed3de5f8cc0 task.stack: ffffbbf80012c000 RIP: 0010:native_smp_send_reschedule+0x37/0x40 RSP: 0018:ffffbbf80012fd10 EFLAGS: 00010082 RAX: 000000000000002f RBX: ffff9ed3dd9cb300 RCX: 0000000000000004 RDX: 0000000080000004 RSI: 0000000000000086 RDI: 00000000ffffffff RBP: ffffbbf80012fd10 R08: 000000000009da7a R09: 0000000000007b9d R10: 0000000000000001 R11: ffffffffbb57c2cd R12: 000000000000000d R13: ffff9ed3de5f8cc0 R14: 0000000000000061 R15: ffff9ed3ded59200 FS: 0000000000000000(0000) GS:ffff9ed3dea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000080686f0 CR3: 000000001b9e0000 CR4: 00000000000006f0 Call Trace: resched_curr+0x61/0xd0 switched_to_rt+0x8f/0xa0 rt_mutex_setprio+0x25c/0x410 task_blocks_on_rt_mutex+0x1b3/0x1f0 rt_mutex_slowlock+0xa9/0x1e0 rt_mutex_lock+0x29/0x30 rcu_boost_kthread+0x127/0x3c0 kthread+0x104/0x140 ? rcu_report_unblock_qs_rnp+0x90/0x90 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x22/0x30 Code: f0 00 0f 92 c0 84 c0 74 14 48 8b 05 34 74 c5 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 a0 c6 fc b9 e8 d5 b5 06 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 a2 d1 13 02 85 c0 75 38 55 48 But the target task's priority has already been adjusted, so the only purpose of switched_to_rt() invoking resched_curr() is to wake up the CPU running some task that needs to be preempted by the boosted task. But the CPU is offline, which presumably means that the task must be migrated to some other CPU, and that this other CPU will undertake any needed preemption at the time of migration. Because the runqueue lock is held when resched_curr() is invoked, we know that the boosted task cannot go anywhere, so it is not necessary to invoke resched_curr() in this particular case. This commit therefore makes switched_to_rt() refrain from invoking resched_curr() when the target CPU is offline. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bug: use %pB in BUG and stack protector failure

2018-03-15T09:56:49Z

commit 0862ca422b79cb5aa70823ee0f07f6b468f86070 upstream. The BUG and stack protector reports were still using a raw %p. This changes it to %pB for more meaningful output. Link: http://lkml.kernel.org/r/20180301225704.GA34198@beast Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Signed-off-by: Kees Cook Reviewed-by: Andrew Morton Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Richard Weinberger , Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

workqueue: Allow retrieval of current task's work struct

2018-03-15T09:56:46Z

commit 27d4ee03078aba88c5e07dcc4917e8d01d046f38 upstream. Introduce a helper to retrieve the current task's work struct if it is a workqueue worker. This allows us to fix a long-standing deadlock in several DRM drivers wherein the ->runtime_suspend callback waits for a specific worker to finish and that worker in turn calls a function which waits for runtime suspend to finish. That function is invoked from multiple call sites and waiting for runtime suspend to finish is the correct thing to do except if it's executing in the context of the worker. Cc: Lai Jiangshan Cc: Dave Airlie Cc: Ben Skeggs Cc: Alex Deucher Acked-by: Tejun Heo Reviewed-by: Lyude Paul Signed-off-by: Lukas Wunner Link: https://patchwork.freedesktop.org/patch/msgid/2d8f603074131eb87e588d2b803a71765bd3a2fd.1518338788.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC in __cpu_map_entry_alloc()

2018-03-15T09:56:44Z

commit 7fc17e909edfb9bf421ee04e981d3d474175c7c7 upstream. There're several implications after commit 0bf7800f1799 ("ptr_ring: try vmalloc() when kmalloc() fails") with the using of vmalloc() since can't allow GFP_ATOMIC but mandate GFP_KERNEL. This will lead a WARN since cpumap try to call with GFP_ATOMIC. Fortunately, entry allocation of cpumap can only be done through syscall path which means GFP_ATOMIC is not necessary, so fixing this by replacing GFP_ATOMIC with GFP_KERNEL. Reported-by: syzbot+1a240cdb1f4cc88819df@syzkaller.appspotmail.com Fixes: 0bf7800f1799 ("ptr_ring: try vmalloc() when kmalloc() fails") Cc: Michal Hocko Cc: Daniel Borkmann Cc: Matthew Wilcox Cc: Jesper Dangaard Brouer Cc: akpm@linux-foundation.org Cc: dhowells@redhat.com Cc: hannes@cmpxchg.org Signed-off-by: Jason Wang Acked-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf: allow xadd only on aligned memory

2018-03-11T15:25:14Z

[ upstream commit ca36960211eb228bcbc7aaebfa0d027368a94c60 ] The requirements around atomic_add() / atomic64_add() resp. their JIT implementations differ across architectures. E.g. while x86_64 seems just fine with BPF's xadd on unaligned memory, on arm64 it triggers via interpreter but also JIT the following crash: [ 830.864985] Unable to handle kernel paging request at virtual address ffff8097d7ed6703 [...] [ 830.916161] Internal error: Oops: 96000021 [#1] SMP [ 830.984755] CPU: 37 PID: 2788 Comm: test_verifier Not tainted 4.16.0-rc2+ #8 [ 830.991790] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.29 07/17/2017 [ 830.998998] pstate: 80400005 (Nzcv daif +PAN -UAO) [ 831.003793] pc : __ll_sc_atomic_add+0x4/0x18 [ 831.008055] lr : ___bpf_prog_run+0x1198/0x1588 [ 831.012485] sp : ffff00001ccabc20 [ 831.015786] x29: ffff00001ccabc20 x28: ffff8017d56a0f00 [ 831.021087] x27: 0000000000000001 x26: 0000000000000000 [ 831.026387] x25: 000000c168d9db98 x24: 0000000000000000 [ 831.031686] x23: ffff000008203878 x22: ffff000009488000 [ 831.036986] x21: ffff000008b14e28 x20: ffff00001ccabcb0 [ 831.042286] x19: ffff0000097b5080 x18: 0000000000000a03 [ 831.047585] x17: 0000000000000000 x16: 0000000000000000 [ 831.052885] x15: 0000ffffaeca8000 x14: 0000000000000000 [ 831.058184] x13: 0000000000000000 x12: 0000000000000000 [ 831.063484] x11: 0000000000000001 x10: 0000000000000000 [ 831.068783] x9 : 0000000000000000 x8 : 0000000000000000 [ 831.074083] x7 : 0000000000000000 x6 : 000580d428000000 [ 831.079383] x5 : 0000000000000018 x4 : 0000000000000000 [ 831.084682] x3 : ffff00001ccabcb0 x2 : 0000000000000001 [ 831.089982] x1 : ffff8097d7ed6703 x0 : 0000000000000001 [ 831.095282] Process test_verifier (pid: 2788, stack limit = 0x0000000018370044) [ 831.102577] Call trace: [ 831.105012] __ll_sc_atomic_add+0x4/0x18 [ 831.108923] __bpf_prog_run32+0x4c/0x70 [ 831.112748] bpf_test_run+0x78/0xf8 [ 831.116224] bpf_prog_test_run_xdp+0xb4/0x120 [ 831.120567] SyS_bpf+0x77c/0x1110 [ 831.123873] el0_svc_naked+0x30/0x34 [ 831.127437] Code: 97fffe97 17ffffec 00000000 f9800031 (885f7c31) Reason for this is because memory is required to be aligned. In case of BPF, we always enforce alignment in terms of stack access, but not when accessing map values or packet data when the underlying arch (e.g. arm64) has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS set. xadd on packet data that is local to us anyway is just wrong, so forbid this case entirely. The only place where xadd makes sense in fact are map values; xadd on stack is wrong as well, but it's been around for much longer. Specifically enforce strict alignment in case of xadd, so that we handle this case generically and avoid such crashes in the first place. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf: add schedule points in percpu arrays management

2018-03-11T15:25:14Z

[ upstream commit 32fff239de37ef226d5b66329dd133f64d63b22d ] syszbot managed to trigger RCU detected stalls in bpf_array_free_percpu() It takes time to allocate a huge percpu map, but even more time to free it. Since we run in process context, use cond_resched() to yield cpu if needed. Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf: fix rcu lockdep warning for lpm_trie map_free callback

2018-03-11T15:25:13Z

[ upstream commit 6c5f61023c5b0edb0c8a64c902fe97c6453b1852 ] Commit 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function") fixed a memory leak and removed unnecessary locks in map_free callback function. Unfortrunately, it introduced a lockdep warning. When lockdep checking is turned on, running tools/testing/selftests/bpf/test_lpm_map will have: [ 98.294321] ============================= [ 98.294807] WARNING: suspicious RCU usage [ 98.295359] 4.16.0-rc2+ #193 Not tainted [ 98.295907] ----------------------------- [ 98.296486] /home/yhs/work/bpf/kernel/bpf/lpm_trie.c:572 suspicious rcu_dereference_check() usage! [ 98.297657] [ 98.297657] other info that might help us debug this: [ 98.297657] [ 98.298663] [ 98.298663] rcu_scheduler_active = 2, debug_locks = 1 [ 98.299536] 2 locks held by kworker/2:1/54: [ 98.300152] #0: ((wq_completion)"events"){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0 [ 98.301381] #1: ((work_completion)(&map->work)){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0 Since actual trie tree removal happens only after no other accesses to the tree are possible, replacing rcu_dereference_protected(*slot, lockdep_is_held(&trie->lock)) with rcu_dereference_protected(*slot, 1) fixed the issue. Fixes: 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function") Reported-by: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Yonghong Song Reviewed-by: Eric Dumazet Acked-by: David S. Miller Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman