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2018-02-08tracing: Fix parsing of globs with a wildcard at the beginningSteven Rostedt (VMware)
Al Viro reported: For substring - sure, but what about something like "*a*b" and "a*b"? AFAICS, filter_parse_regex() ends up with identical results in both cases - MATCH_GLOB and *search = "a*b". And no way for the caller to tell one from another. Testing this with the following: # cd /sys/kernel/tracing # echo '*raw*lock' > set_ftrace_filter bash: echo: write error: Invalid argument With this patch: # echo '*raw*lock' > set_ftrace_filter # cat set_ftrace_filter _raw_read_trylock _raw_write_trylock _raw_read_unlock _raw_spin_unlock _raw_write_unlock _raw_spin_trylock _raw_spin_lock _raw_write_lock _raw_read_lock Al recommended not setting the search buffer to skip the first '*' unless we know we are not using MATCH_GLOB. This implements his suggested logic. Link: http://lkml.kernel.org/r/20180127170748.GF13338@ZenIV.linux.org.uk Cc: stable@vger.kernel.org Fixes: 60f1d5e3bac44 ("ftrace: Support full glob matching") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Suggsted-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-02-08ftrace: Remove incorrect setting of glob search fieldSteven Rostedt (VMware)
__unregister_ftrace_function_probe() will incorrectly parse the glob filter because it resets the search variable that was setup by filter_parse_regex(). Al Viro reported this: After that call of filter_parse_regex() we could have func_g.search not equal to glob only if glob started with '!' or '*'. In the former case we would've buggered off with -EINVAL (not = 1). In the latter we would've set func_g.search equal to glob + 1, calculated the length of that thing in func_g.len and proceeded to reset func_g.search back to glob. Suppose the glob is e.g. *foo*. We end up with func_g.type = MATCH_MIDDLE_ONLY; func_g.len = 3; func_g.search = "*foo"; Feeding that to ftrace_match_record() will not do anything sane - we will be looking for names containing "*foo" (->len is ignored for that one). Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk Cc: stable@vger.kernel.org Fixes: 3ba009297149f ("ftrace: Introduce ftrace_glob structure") Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23ftrace: Mark function tracer test functions noinline/nocloneAndi Kleen
The ftrace function tracer self tests calls some functions to verify the get traced. This relies on them not being inlined. Previously this was ensured by putting them into another file, but with LTO the compiler can inline across files, which makes the tests fail. Mark these functions as noinline and noclone. Link: http://lkml.kernel.org/r/20171221233732.31896-1-andi@firstfloor.org Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23trace_uprobe: Display correct offset in uprobe_eventsRavi Bangoria
Recently, how the pointers being printed with %p has been changed by commit ad67b74d2469 ("printk: hash addresses printed with %p"). This is causing a regression while showing offset in the uprobe_events file. Instead of %p, use %px to display offset. Before patch: # perf probe -vv -x /tmp/a.out main Opening /sys/kernel/debug/tracing//uprobe_events write=1 Writing event: p:probe_a/main /tmp/a.out:0x58c # cat /sys/kernel/debug/tracing/uprobe_events p:probe_a/main /tmp/a.out:0x0000000049a0f352 After patch: # cat /sys/kernel/debug/tracing/uprobe_events p:probe_a/main /tmp/a.out:0x000000000000058c Link: http://lkml.kernel.org/r/20180106054246.15375-1-ravi.bangoria@linux.vnet.ibm.com Cc: stable@vger.kernel.org Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23tracing: Make sure the parsed string always terminates with '\0'Changbin Du
Always mark the parsed string with a terminated nul '\0' character. This removes the need for the users to have to append the '\0' before using the parsed string. Link: http://lkml.kernel.org/r/1516093350-12045-4-git-send-email-changbin.du@intel.com Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23tracing: Clear parser->idx if only spaces are readChangbin Du
If only spaces were read while parsing the next string, then parser->idx should be cleared in order to make trace_parser_loaded() return false. Link: http://lkml.kernel.org/r/1516093350-12045-3-git-send-email-changbin.du@intel.com Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23tracing: Detect the string nul character when parsing user input stringChangbin Du
User space can pass in a C nul character '\0' along with its input. The function trace_get_user() will try to process it as a normal character, and that will fail to parse. open("/sys/kernel/debug/tracing//set_ftrace_pid", O_WRONLY|O_TRUNC) = 3 write(3, " \0", 2) = -1 EINVAL (Invalid argument) while parse can handle spaces, so below works. $ echo "" > set_ftrace_pid $ echo " " > set_ftrace_pid $ echo -n " " > set_ftrace_pid Have the parser stop on '\0' and cease any further parsing. Only process the characters up to the nul '\0' character and do not process it. Link: http://lkml.kernel.org/r/1516093350-12045-2-git-send-email-changbin.du@intel.com Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23tracing: Update stack trace skipping for ORC unwinderSteven Rostedt (VMware)
With the addition of ORC unwinder and FRAME POINTER unwinder, the stack trace skipping requirements have changed. I went through the tracing stack trace dumps with ORC and with frame pointers and recalculated the proper values. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23ftrace, orc, x86: Handle ftrace dynamically allocated trampolinesSteven Rostedt (VMware)
The function tracer can create a dynamically allocated trampoline that is called by the function mcount or fentry hook that is used to call the function callback that is registered. The problem is that the orc undwinder will bail if it encounters one of these trampolines. This breaks the stack trace of function callbacks, which include the stack tracer and setting the stack trace for individual functions. Since these dynamic trampolines are basically copies of the static ftrace trampolines defined in ftrace_*.S, we do not need to create new orc entries for the dynamic trampolines. Finding the return address on the stack will be identical as the functions that were copied to create the dynamic trampolines. When encountering a ftrace dynamic trampoline, we can just use the orc entry of the ftrace static function that was copied for that trampoline. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-21Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fix from Thomas Gleixner: "A single fix for the new matrix allocator to prevent vector exhaustion by certain network drivers which allocate gazillions of unused vectors which cannot be put into reservation mode due to MSI and the lack of MSI entry masking. The fix/workaround is to spread the vectors across CPUs by searching the supplied target CPU mask for the CPU with the smallest number of allocated vectors" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irq/matrix: Spread interrupts on allocation
2018-01-19Merge tag 'trace-v4.15-rc4-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Two more small fixes - The conversion of enums into their actual numbers to display in the event format file had an off-by-one bug, that could cause an enum not to be converted, and break user space parsing tools. - A fix to a previous fix to bring back the context recursion checks. The interrupt case checks for NMI, IRQ and softirq, but the softirq returned the same number regardless if it was set or not, although the logic would force it to be set if it were hit" * tag 'trace-v4.15-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix converting enum's from the map in trace_event_eval_update() ring-buffer: Fix duplicate results in mapping context to bits in recursive lock
2018-01-19Merge branch 'for-4.15-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fix from Tejun Heo: "cgroup.threads should be delegatable (ie. a container should be able to write to it from inside) but was missing the flag. The change is very low risk" * 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: make cgroup.threads delegatable
2018-01-19Merge branch 'for-4.15-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq Pull workqueue fixlet from Tejun Heo: "One patch to add touch_nmi_watchdog() while dumping workqueue debug messages to avoid triggering the lockup detector spuriously. The change is very low risk" * 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: avoid hard lockups in show_workqueue_state()
2018-01-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) Fix BPF divides by zero, from Eric Dumazet and Alexei Starovoitov. 2) Reject stores into bpf context via st and xadd, from Daniel Borkmann. 3) Fix a memory leak in TUN, from Cong Wang. 4) Disable RX aggregation on a specific troublesome configuration of r8152 in a Dell TB16b dock. 5) Fix sw_ctx leak in tls, from Sabrina Dubroca. 6) Fix program replacement in cls_bpf, from Daniel Borkmann. 7) Fix uninitialized station_info structures in cfg80211, from Johannes Berg. 8) Fix miscalculation of transport header offset field in flow dissector, from Eric Dumazet. 9) Fix LPM tree leak on failure in mlxsw driver, from Ido Schimmel. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (29 commits) ibmvnic: Fix IPv6 packet descriptors ibmvnic: Fix IP offload control buffer ipv6: don't let tb6_root node share routes with other node ip6_gre: init dev->mtu and dev->hard_header_len correctly mlxsw: spectrum_router: Free LPM tree upon failure flow_dissector: properly cap thoff field fm10k: mark PM functions as __maybe_unused cfg80211: fix station info handling bugs netlink: reset extack earlier in netlink_rcv_skb can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once bpf: mark dst unknown on inconsistent {s, u}bounds adjustments bpf: fix cls_bpf on filter replace Net: ethernet: ti: netcp: Fix inbound ping crash if MTU size is greater than 1500 tls: reset crypto_info when do_tls_setsockopt_tx fails tls: return -EBUSY if crypto_info is already set tls: fix sw_ctx leak net/tls: Only attach to sockets in ESTABLISHED state net: fs_enet: do not call phy_stop() in interrupts r8152: disable RX aggregation on Dell TB16 dock ...
2018-01-18tracing: Fix converting enum's from the map in trace_event_eval_update()Steven Rostedt (VMware)
Since enums do not get converted by the TRACE_EVENT macro into their values, the event format displaces the enum name and not the value. This breaks tools like perf and trace-cmd that need to interpret the raw binary data. To solve this, an enum map was created to convert these enums into their actual numbers on boot up. This is done by TRACE_EVENTS() adding a TRACE_DEFINE_ENUM() macro. Some enums were not being converted. This was caused by an optization that had a bug in it. All calls get checked against this enum map to see if it should be converted or not, and it compares the call's system to the system that the enum map was created under. If they match, then they call is processed. To cut down on the number of iterations needed to find the maps with a matching system, since calls and maps are grouped by system, when a match is made, the index into the map array is saved, so that the next call, if it belongs to the same system as the previous call, could start right at that array index and not have to scan all the previous arrays. The problem was, the saved index was used as the variable to know if this is a call in a new system or not. If the index was zero, it was assumed that the call is in a new system and would keep incrementing the saved index until it found a matching system. The issue arises when the first matching system was at index zero. The next map, if it belonged to the same system, would then think it was the first match and increment the index to one. If the next call belong to the same system, it would begin its search of the maps off by one, and miss the first enum that should be converted. This left a single enum not converted properly. Also add a comment to describe exactly what that index was for. It took me a bit too long to figure out what I was thinking when debugging this issue. Link: http://lkml.kernel.org/r/717BE572-2070-4C1E-9902-9F2E0FEDA4F8@oracle.com Cc: stable@vger.kernel.org Fixes: 0c564a538aa93 ("tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values") Reported-by: Chuck Lever <chuck.lever@oracle.com> Teste-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-18ring-buffer: Fix duplicate results in mapping context to bits in recursive lockSteven Rostedt (VMware)
In bringing back the context checks, the code checks first if its normal (non-interrupt) context, and then for NMI then IRQ then softirq. The final check is redundant. Since the if branch is only hit if the context is one of NMI, IRQ, or SOFTIRQ, if it's not NMI or IRQ there's no reason to check if it is SOFTIRQ. The current code returns the same result even if its not a SOFTIRQ. Which is confusing. pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ Is redundant as RB_CTX_SOFTIRQ *is* 2! Fixes: a0e3a18f4baf ("ring-buffer: Bring back context level recursive checks") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf 2018-01-18 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Fix a divide by zero due to wrong if (src_reg == 0) check in 64-bit mode. Properly handle this in interpreter and mask it also generically in verifier to guard against similar checks in JITs, from Eric and Alexei. 2) Fix a bug in arm64 JIT when tail calls are involved and progs have different stack sizes, from Daniel. 3) Reject stores into BPF context that are not expected BPF_STX | BPF_MEM variant, from Daniel. 4) Mark dst reg as unknown on {s,u}bounds adjustments when the src reg has derived bounds from dead branches, from Daniel. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-18irq/matrix: Spread interrupts on allocationThomas Gleixner
Keith reported an issue with vector space exhaustion on a server machine which is caused by the i40e driver allocating 168 MSI interrupts when the driver is initialized, even when most of these interrupts are not used at all. The x86 vector allocation code tries to avoid the immediate allocation with the reservation mode, but the card uses MSI and does not support MSI entry masking, which prevents reservation mode and requires immediate vector allocation. The matrix allocator is a bit naive and prefers the first CPU in the cpumask which describes the possible target CPUs for an allocation. That results in allocating all 168 vectors on CPU0 which later causes vector space exhaustion when the NVMe driver tries to allocate managed interrupts on each CPU for the per CPU queues. Avoid this by finding the CPU which has the lowest vector allocation count to spread out the non managed interrupt accross the possible target CPUs. Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator") Reported-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Keith Busch <keith.busch@intel.com> Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801171557330.1777@nanos
2018-01-17bpf: mark dst unknown on inconsistent {s, u}bounds adjustmentsDaniel Borkmann
syzkaller generated a BPF proglet and triggered a warning with the following: 0: (b7) r0 = 0 1: (d5) if r0 s<= 0x0 goto pc+0 R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0 2: (1f) r0 -= r1 R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0 verifier internal error: known but bad sbounds What happens is that in the first insn, r0's min/max value are both 0 due to the immediate assignment, later in the jsle test the bounds are updated for the min value in the false path, meaning, they yield smin_val = 1, smax_val = 0, and when ctx pointer is subtracted from r0, verifier bails out with the internal error and throwing a WARN since smin_val != smax_val for the known constant. For min_val > max_val scenario it means that reg_set_min_max() and reg_set_min_max_inv() (which both refine existing bounds) demonstrated that such branch cannot be taken at runtime. In above scenario for the case where it will be taken, the existing [0, 0] bounds are kept intact. Meaning, the rejection is not due to a verifier internal error, and therefore the WARN() is not necessary either. We could just reject such cases in adjust_{ptr,scalar}_min_max_vals() when either known scalars have smin_val != smax_val or umin_val != umax_val or any scalar reg with bounds smin_val > smax_val or umin_val > umax_val. However, there may be a small risk of breakage of buggy programs, so handle this more gracefully and in adjust_{ptr,scalar}_min_max_vals() just taint the dst reg as unknown scalar when we see ops with such kind of src reg. Reported-by: syzbot+6d362cadd45dc0a12ba4@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-17Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Ingo Molnar: "A delayacct statistics correctness fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: delayacct: Account blkio completion on the correct task
2018-01-17Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "Two futex fixes: a input parameters robustness fix, and futex race fixes" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Prevent overflow by strengthen input validation futex: Avoid violating the 10th rule of futex
2018-01-17Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "A one-liner fix which prevents deferrable timers becoming stale when the system does not switch into NOHZ mode" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers: Unconditionally check deferrable base
2018-01-16bpf: reject stores into ctx via st and xaddDaniel Borkmann
Alexei found that verifier does not reject stores into context via BPF_ST instead of BPF_STX. And while looking at it, we also should not allow XADD variant of BPF_STX. The context rewriter is only assuming either BPF_LDX_MEM- or BPF_STX_MEM-type operations, thus reject anything other than that so that assumptions in the rewriter properly hold. Add test cases as well for BPF selftests. Fixes: d691f9e8d440 ("bpf: allow programs to write to certain skb fields") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) Two read past end of buffer fixes in AF_KEY, from Eric Biggers. 2) Memory leak in key_notify_policy(), from Steffen Klassert. 3) Fix overflow with bpf arrays, from Daniel Borkmann. 4) Fix RDMA regression with mlx5 due to mlx5 no longer using pci_irq_get_affinity(), from Saeed Mahameed. 5) Missing RCU read locking in nl80211_send_iface() when it calls ieee80211_bss_get_ie(), from Dominik Brodowski. 6) cfg80211 should check dev_set_name()'s return value, from Johannes Berg. 7) Missing module license tag in 9p protocol, from Stephen Hemminger. 8) Fix crash due to too small MTU in udp ipv6 sendmsg, from Mike Maloney. 9) Fix endless loop in netlink extack code, from David Ahern. 10) TLS socket layer sets inverted error codes, resulting in an endless loop. From Robert Hering. 11) Revert openvswitch erspan tunnel support, it's mis-designed and we need to kill it before it goes into a real release. From William Tu. 12) Fix lan78xx failures in full speed USB mode, from Yuiko Oshino. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits) net, sched: fix panic when updating miniq {b,q}stats qed: Fix potential use-after-free in qed_spq_post() nfp: use the correct index for link speed table lan78xx: Fix failure in USB Full Speed sctp: do not allow the v4 socket to bind a v4mapped v6 address sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf sctp: reinit stream if stream outcnt has been change by sinit in sendmsg ibmvnic: Fix pending MAC address changes netlink: extack: avoid parenthesized string constant warning ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY net: Allow neigh contructor functions ability to modify the primary_key sh_eth: fix dumping ARSTR Revert "openvswitch: Add erspan tunnel support." net/tls: Fix inverted error codes to avoid endless loop ipv6: ip6_make_skb() needs to clear cork.base.dst sctp: avoid compiler warning on implicit fallthru net: ipv4: Make "ip route get" match iif lo rules again. netlink: extack needs to be reset each time through loop tipc: fix a memory leak in tipc_nl_node_get_link() ipv6: fix udpv6 sendmsg crash caused by too small MTU ...
2018-01-16Merge tag 'trace-v4.15-rc4-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: - Bring back context level recursive protection in ring buffer. The simpler counter protection failed, due to a path when tracing with trace_clock_global() as it could not be reentrant and depended on the ring buffer recursive protection to keep that from happening. - Prevent branch profiling when FORTIFY_SOURCE is enabled. It causes 50 - 60 MB in warning messages. Branch profiling should never be run on production systems, so there's no reason that it needs to be enabled with FORTIFY_SOURCE. * tag 'trace-v4.15-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Prevent PROFILE_ALL_BRANCHES when FORTIFY_SOURCE=y ring-buffer: Bring back context level recursive checks
2018-01-16delayacct: Account blkio completion on the correct taskJosh Snyder
Before commit: e33a9bba85a8 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler") delayacct_blkio_end() was called after context-switching into the task which completed I/O. This resulted in double counting: the task would account a delay both waiting for I/O and for time spent in the runqueue. With e33a9bba85a8, delayacct_blkio_end() is called by try_to_wake_up(). In ttwu, we have not yet context-switched. This is more correct, in that the delay accounting ends when the I/O is complete. But delayacct_blkio_end() relies on 'get_current()', and we have not yet context-switched into the task whose I/O completed. This results in the wrong task having its delay accounting statistics updated. Instead of doing that, pass the task_struct being woken to delayacct_blkio_end(), so that it can update the statistics of the correct task. Signed-off-by: Josh Snyder <joshs@netflix.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Balbir Singh <bsingharora@gmail.com> Cc: <stable@vger.kernel.org> Cc: Brendan Gregg <bgregg@netflix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-block@vger.kernel.org Fixes: e33a9bba85a8 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler") Link: http://lkml.kernel.org/r/1513613712-571-1-git-send-email-joshs@netflix.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-15tracing: Prevent PROFILE_ALL_BRANCHES when FORTIFY_SOURCE=yRandy Dunlap
I regularly get 50 MB - 60 MB files during kernel randconfig builds. These large files mostly contain (many repeats of; e.g., 124,594): In file included from ../include/linux/string.h:6:0, from ../include/linux/uuid.h:20, from ../include/linux/mod_devicetable.h:13, from ../scripts/mod/devicetable-offsets.c:3: ../include/linux/compiler.h:64:4: warning: '______f' is static but declared in inline function 'strcpy' which is not static [enabled by default] ______f = { \ ^ ../include/linux/compiler.h:56:23: note: in expansion of macro '__trace_if' ^ ../include/linux/string.h:425:2: note: in expansion of macro 'if' if (p_size == (size_t)-1 && q_size == (size_t)-1) ^ This only happens when CONFIG_FORTIFY_SOURCE=y and CONFIG_PROFILE_ALL_BRANCHES=y, so prevent PROFILE_ALL_BRANCHES if FORTIFY_SOURCE=y. Link: http://lkml.kernel.org/r/9199446b-a141-c0c3-9678-a3f9107f2750@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-15ring-buffer: Bring back context level recursive checksSteven Rostedt (VMware)
Commit 1a149d7d3f45 ("ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler") replaced the context level recursion checks with a simple counter. This would prevent the ring buffer code from recursively calling itself more than the max number of contexts that exist (Normal, softirq, irq, nmi). But this change caused a lockup in a specific case, which was during suspend and resume using a global clock. Adding a stack dump to see where this occurred, the issue was in the trace global clock itself: trace_buffer_lock_reserve+0x1c/0x50 __trace_graph_entry+0x2d/0x90 trace_graph_entry+0xe8/0x200 prepare_ftrace_return+0x69/0xc0 ftrace_graph_caller+0x78/0xa8 queued_spin_lock_slowpath+0x5/0x1d0 trace_clock_global+0xb0/0xc0 ring_buffer_lock_reserve+0xf9/0x390 The function graph tracer traced queued_spin_lock_slowpath that was called by trace_clock_global. This pointed out that the trace_clock_global() is not reentrant, as it takes a spin lock. It depended on the ring buffer recursive lock from letting that happen. By removing the context detection and adding just a max number of allowable recursions, it allowed the trace_clock_global() to be entered again and try to retake the spinlock it already held, causing a deadlock. Fixes: 1a149d7d3f45 ("ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler") Reported-by: David Weinehall <david.weinehall@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-14timers: Unconditionally check deferrable baseThomas Gleixner
When the timer base is checked for expired timers then the deferrable base must be checked as well. This was missed when making the deferrable base independent of base::nohz_active. Fixes: ced6d5c11d3e ("timers: Use deferrable base independent of base::nohz_active") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Cc: rt@linutronix.de
2018-01-14bpf: fix 32-bit divide by zeroAlexei Starovoitov
due to some JITs doing if (src_reg == 0) check in 64-bit mode for div/mod operations mask upper 32-bits of src register before doing the check Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT") Fixes: 7a12b5031c6b ("sparc64: Add eBPF JIT.") Reported-by: syzbot+48340bb518e88849e2e3@syzkaller.appspotmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-01-14futex: Prevent overflow by strengthen input validationLi Jinyue
UBSAN reports signed integer overflow in kernel/futex.c: UBSAN: Undefined behaviour in kernel/futex.c:2041:18 signed integer overflow: 0 - -2147483648 cannot be represented in type 'int' Add a sanity check to catch negative values of nr_wake and nr_requeue. Signed-off-by: Li Jinyue <lijinyue@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: peterz@infradead.org Cc: dvhart@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.com
2018-01-14futex: Avoid violating the 10th rule of futexPeter Zijlstra
Julia reported futex state corruption in the following scenario: waiter waker stealer (prio > waiter) futex(WAIT_REQUEUE_PI, uaddr, uaddr2, timeout=[N ms]) futex_wait_requeue_pi() futex_wait_queue_me() freezable_schedule() <scheduled out> futex(LOCK_PI, uaddr2) futex(CMP_REQUEUE_PI, uaddr, uaddr2, 1, 0) /* requeues waiter to uaddr2 */ futex(UNLOCK_PI, uaddr2) wake_futex_pi() cmp_futex_value_locked(uaddr2, waiter) wake_up_q() <woken by waker> <hrtimer_wakeup() fires, clears sleeper->task> futex(LOCK_PI, uaddr2) __rt_mutex_start_proxy_lock() try_to_take_rt_mutex() /* steals lock */ rt_mutex_set_owner(lock, stealer) <preempted> <scheduled in> rt_mutex_wait_proxy_lock() __rt_mutex_slowlock() try_to_take_rt_mutex() /* fails, lock held by stealer */ if (timeout && !timeout->task) return -ETIMEDOUT; fixup_owner() /* lock wasn't acquired, so, fixup_pi_state_owner skipped */ return -ETIMEDOUT; /* At this point, we've returned -ETIMEDOUT to userspace, but the * futex word shows waiter to be the owner, and the pi_mutex has * stealer as the owner */ futex_lock(LOCK_PI, uaddr2) -> bails with EDEADLK, futex word says we're owner. And suggested that what commit: 73d786bd043e ("futex: Rework inconsistent rt_mutex/futex_q state") removes from fixup_owner() looks to be just what is needed. And indeed it is -- I completely missed that requeue_pi could also result in this case. So we need to restore that, except that subsequent patches, like commit: 16ffa12d7425 ("futex: Pull rt_mutex_futex_unlock() out from under hb->lock") changed all the locking rules. Even without that, the sequence: - if (rt_mutex_futex_trylock(&q->pi_state->pi_mutex)) { - locked = 1; - goto out; - } - raw_spin_lock_irq(&q->pi_state->pi_mutex.wait_lock); - owner = rt_mutex_owner(&q->pi_state->pi_mutex); - if (!owner) - owner = rt_mutex_next_owner(&q->pi_state->pi_mutex); - raw_spin_unlock_irq(&q->pi_state->pi_mutex.wait_lock); - ret = fixup_pi_state_owner(uaddr, q, owner); already suggests there were races; otherwise we'd never have to look at next_owner. So instead of doing 3 consecutive wait_lock sections with who knows what races, we do it all in a single section. Additionally, the usage of pi_state->owner in fixup_owner() was only safe because only the rt_mutex owner would modify it, which this additional case wrecks. Luckily the values can only change away and not to the value we're testing, this means we can do a speculative test and double check once we have the wait_lock. Fixes: 73d786bd043e ("futex: Rework inconsistent rt_mutex/futex_q state") Reported-by: Julia Cartwright <julia@ni.com> Reported-by: Gratian Crisan <gratian.crisan@ni.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Julia Cartwright <julia@ni.com> Tested-by: Gratian Crisan <gratian.crisan@ni.com> Cc: Darren Hart <dvhart@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20171208124939.7livp7no2ov65rrc@hirez.programming.kicks-ass.net
2018-01-14bpf: fix divides by zeroEric Dumazet
Divides by zero are not nice, lets avoid them if possible. Also do_div() seems not needed when dealing with 32bit operands, but this seems a minor detail. Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-13Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge misc fixlets from Andrew Morton: "4 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: tools/objtool/Makefile: don't assume sync-check.sh is executable kdump: write correct address of mem_section into vmcoreinfo kmemleak: allow to coexist with fault injection MAINTAINERS, nilfs2: change project home URLs
2018-01-13kdump: write correct address of mem_section into vmcoreinfoKirill A. Shutemov
Depending on configuration mem_section can now be an array or a pointer to an array allocated dynamically. In most cases, we can continue to refer to it as 'mem_section' regardless of what it is. But there's one exception: '&mem_section' means "address of the array" if mem_section is an array, but if mem_section is a pointer, it would mean "address of the pointer". We've stepped onto this in kdump code. VMCOREINFO_SYMBOL(mem_section) writes down address of pointer into vmcoreinfo, not array as we wanted. Let's introduce VMCOREINFO_SYMBOL_ARRAY() that would handle the situation correctly for both cases. Link: http://lkml.kernel.org/r/20180112162532.35896-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y") Acked-by: Baoquan He <bhe@redhat.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-12workqueue: avoid hard lockups in show_workqueue_state()Sergey Senozhatsky
show_workqueue_state() can print out a lot of messages while being in atomic context, e.g. sysrq-t -> show_workqueue_state(). If the console device is slow it may end up triggering NMI hard lockup watchdog. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v4.5+
2018-01-12Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "A Kconfig fix, a build fix and a membarrier bug fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: membarrier: Disable preemption when calling smp_call_function_many() sched/isolation: Make CONFIG_CPU_ISOLATION=y depend on SMP or COMPILE_TEST ia64, sched/cputime: Fix build error if CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y
2018-01-12Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "No functional effects intended: removes leftovers from recent lockdep and refcounts work" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/refcounts: Remove stale comment from the ARCH_HAS_REFCOUNT Kconfig entry locking/lockdep: Remove cross-release leftovers locking/Documentation: Remove stale crossrelease_fullstack parameter
2018-01-10bpf, array: fix overflow in max_entries and undefined behavior in index_maskDaniel Borkmann
syzkaller tried to alloc a map with 0xfffffffd entries out of a userns, and thus unprivileged. With the recently added logic in b2157399cc98 ("bpf: prevent out-of-bounds speculation") we round this up to the next power of two value for max_entries for unprivileged such that we can apply proper masking into potentially zeroed out map slots. However, this will generate an index_mask of 0xffffffff, and therefore a + 1 will let this overflow into new max_entries of 0. This will pass allocation, etc, and later on map access we still enforce on the original attr->max_entries value which was 0xfffffffd, therefore triggering GPF all over the place. Thus bail out on overflow in such case. Moreover, on 32 bit archs roundup_pow_of_two() can also not be used, since fls_long(max_entries - 1) can result in 32 and 1UL << 32 in 32 bit space is undefined. Therefore, do this by hand in a 64 bit variable. This fixes all the issues triggered by syzkaller's reproducers. Fixes: b2157399cc98 ("bpf: prevent out-of-bounds speculation") Reported-by: syzbot+b0efb8e572d01bce1ae0@syzkaller.appspotmail.com Reported-by: syzbot+6c15e9744f75f2364773@syzkaller.appspotmail.com Reported-by: syzbot+d2f5524fb46fd3b312ee@syzkaller.appspotmail.com Reported-by: syzbot+61d23c95395cc90dbc2b@syzkaller.appspotmail.com Reported-by: syzbot+0d363c942452cca68c01@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-10bpf: arsh is not supported in 32 bit alu thus reject itDaniel Borkmann
The following snippet was throwing an 'unknown opcode cc' warning in BPF interpreter: 0: (18) r0 = 0x0 2: (7b) *(u64 *)(r10 -16) = r0 3: (cc) (u32) r0 s>>= (u32) r0 4: (95) exit Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X} generation, not all of them do and interpreter does neither. We can leave existing ones and implement it later in bpf-next for the remaining ones, but reject this properly in verifier for the time being. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-10bpf: fix spelling mistake: "obusing" -> "abusing"Colin Ian King
Trivial fix to spelling mistake in error message text. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-10cgroup: make cgroup.threads delegatableRoman Gushchin
Make cgroup.threads file delegatable. The behavior of cgroup.threads should follow the behavior of cgroup.procs. Signed-off-by: Roman Gushchin <guro@fb.com> Discovered-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2018-01-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf 2018-01-09 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Prevent out-of-bounds speculation in BPF maps by masking the index after bounds checks in order to fix spectre v1, and add an option BPF_JIT_ALWAYS_ON into Kconfig that allows for removing the BPF interpreter from the kernel in favor of JIT-only mode to make spectre v2 harder, from Alexei. 2) Remove false sharing of map refcount with max_entries which was used in spectre v1, from Daniel. 3) Add a missing NULL psock check in sockmap in order to fix a race, from John. 4) Fix test_align BPF selftest case since a recent change in verifier rejects the bit-wise arithmetic on pointers earlier but test_align update was missing, from Alexei. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10membarrier: Disable preemption when calling smp_call_function_many()Mathieu Desnoyers
smp_call_function_many() requires disabling preemption around the call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: <stable@vger.kernel.org> # v4.14+ Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Andrew Hunter <ahh@google.com> Cc: Avi Kivity <avi@scylladb.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Dave Watson <davejwatson@fb.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maged Michael <maged.michael@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171215192310.25293-1-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-09bpf: introduce BPF_JIT_ALWAYS_ON configAlexei Starovoitov
The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715. A quote from goolge project zero blog: "At this point, it would normally be necessary to locate gadgets in the host kernel code that can be used to actually leak data by reading from an attacker-controlled location, shifting and masking the result appropriately and then using the result of that as offset to an attacker-controlled address for a load. But piecing gadgets together and figuring out which ones work in a speculation context seems annoying. So instead, we decided to use the eBPF interpreter, which is built into the host kernel - while there is no legitimate way to invoke it from inside a VM, the presence of the code in the host kernel's text section is sufficient to make it usable for the attack, just like with ordinary ROP gadgets." To make attacker job harder introduce BPF_JIT_ALWAYS_ON config option that removes interpreter from the kernel in favor of JIT-only mode. So far eBPF JIT is supported by: x64, arm64, arm32, sparc64, s390, powerpc64, mips64 The start of JITed program is randomized and code page is marked as read-only. In addition "constant blinding" can be turned on with net.core.bpf_jit_harden v2->v3: - move __bpf_prog_ret0 under ifdef (Daniel) v1->v2: - fix init order, test_bpf and cBPF (Daniel's feedback) - fix offloaded bpf (Jakub's feedback) - add 'return 0' dummy in case something can invoke prog->bpf_func - retarget bpf tree. For bpf-next the patch would need one extra hunk. It will be sent when the trees are merged back to net-next Considered doing: int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT; but it seems better to land the patch as-is and in bpf-next remove bpf_jit_enable global variable from all JITs, consolidate in one place and remove this jit_init() function. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-01-09bpf: prevent out-of-bounds speculationAlexei Starovoitov
Under speculation, CPUs may mis-predict branches in bounds checks. Thus, memory accesses under a bounds check may be speculated even if the bounds check fails, providing a primitive for building a side channel. To avoid leaking kernel data round up array-based maps and mask the index after bounds check, so speculated load with out of bounds index will load either valid value from the array or zero from the padded area. Unconditionally mask index for all array types even when max_entries are not rounded to power of 2 for root user. When map is created by unpriv user generate a sequence of bpf insns that includes AND operation to make sure that JITed code includes the same 'index & index_mask' operation. If prog_array map is created by unpriv user replace bpf_tail_call(ctx, map, index); with if (index >= max_entries) { index &= map->index_mask; bpf_tail_call(ctx, map, index); } (along with roundup to power 2) to prevent out-of-bounds speculation. There is secondary redundant 'if (index >= max_entries)' in the interpreter and in all JITs, but they can be optimized later if necessary. Other array-like maps (cpumap, devmap, sockmap, perf_event_array, cgroup_array) cannot be used by unpriv, so no changes there. That fixes bpf side of "Variant 1: bounds check bypass (CVE-2017-5753)" on all architectures with and without JIT. v2->v3: Daniel noticed that attack potentially can be crafted via syscall commands without loading the program, so add masking to those paths as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-01-08Merge branch 'for-4.15-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "This contains fixes for the following two non-trivial issues: - The task iterator got broken while adding thread mode support for v4.14. It was less visible because it only triggers when both cgroup1 and cgroup2 hierarchies are in use. The recent versions of systemd uses cgroup2 for process management even when cgroup1 is used for resource control exposing this issue. - cpuset CPU hotplug path could deadlock when racing against exits. There also are two patches to replace unlimited strcpy() usages with strlcpy()" * 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix css_task_iter crash on CSS_TASK_ITER_PROC cgroup: Fix deadlock in cpu hotplug path cgroup: use strlcpy() instead of strscpy() to avoid spurious warning cgroup: avoid copying strings longer than the buffers
2018-01-08locking/lockdep: Remove cross-release leftoversIngo Molnar
There's two cross-release leftover facilities: - the crossrelease_hist_*() irq-tracing callbacks (NOPs currently) - the complete_release_commit() callback (NOP as well) Remove them. Cc: David Sterba <dsterba@suse.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-06Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro: - untangle sys_close() abuses in xt_bpf - deal with register_shrinker() failures in sget() * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fix "netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'" sget(): handle failures of register_shrinker() mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed.
2018-01-07bpf: sockmap missing NULL psock checkJohn Fastabend
Add psock NULL check to handle a racing sock event that can get the sk_callback_lock before this case but after xchg happens causing the refcnt to hit zero and sock user data (psock) to be null and queued for garbage collection. Also add a comment in the code because this is a bit subtle and not obvious in my opinion. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>