- 01 Nov, 2017 14 commits
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Ricardo Neri authored
The segment descriptor contains information that is relevant to how linear addresses need to be computed. It contains the default size of addresses as well as the base address of the segment. Thus, given a segment selector, we ought to look at segment descriptor to correctly calculate the linear address. In protected mode, the segment selector might indicate a segment descriptor from either the global descriptor table or a local descriptor table. Both cases are considered in this function. This function is a prerequisite for functions in subsequent commits that will obtain the aforementioned attributes of the segment descriptor. Improvements-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Reviewed-by:
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Ricardo Neri authored
When computing a linear address and segmentation is used, we need to know the base address of the segment involved in the computation. In most of the cases, the segment base address will be zero as in USER_DS/USER32_DS. However, it may be possible that a user space program defines its own segments via a local descriptor table. In such a case, the segment base address may not be zero. Thus, the segment base address is needed to calculate correctly the linear address. If running in protected mode, the segment selector to be used when computing a linear address is determined by either any of segment override prefixes in the instruction or inferred from the registers involved in the computation of the effective address; in that order. Also, there are cases when the segment override prefixes shall be ignored (i.e., code segments are always selected by the CS segment register; string instructions always use the ES segment register when using rDI register as operand). In long mode, segment registers are ignored, except for FS and GS. In these two cases, base addresses are obtained from the respective MSRs. For clarity, this process can be split into four steps (and an equal number of functions): determine if segment prefixes overrides can be used; parse the segment override prefixes, and use them if found; if not found or cannot be used, use the default segment registers associated with the operand registers. Once the segment register to use has been identified, read its value to obtain the segment selector. The method to obtain the segment selector depends on several factors. In 32-bit builds, segment selectors are saved into a pt_regs structure when switching to kernel mode. The same is also true for virtual-8086 mode. In 64-bit builds, segmentation is mostly ignored, except when running a program in 32-bit legacy mode. In this case, CS and SS can be obtained from pt_regs. DS, ES, FS and GS can be read directly from the respective segment registers. In order to identify the segment registers, a new set of #defines is introduced. It also includes two special identifiers. One of them indicates when the default segment register associated with instruction operands shall be used. Another one indicates that the contents of the segment register shall be ignored; this identifier is used when in long mode. Improvements-by:
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Ricardo Neri authored
String instructions are special because, in protected mode, the linear address is always obtained via the ES segment register in operands that use the (E)DI register; the DS segment register in operands that use the (E)SI register. Furthermore, segment override prefixes are ignored when calculating a linear address involving the (E)DI register; segment override prefixes can be used when calculating linear addresses involving the (E)SI register. It follows that linear addresses are calculated differently for the case of string instructions. The purpose of this utility function is to identify such instructions for callers to determine a linear address correctly. Note that this function only identifies string instructions; it does not determine what segment register to use in the address computation. That is left to callers. A subsequent commmit introduces a function to determine the segment register to use given the instruction, operands and segment override prefixes. Signed-off-by:
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Ricardo Neri authored
The function get_reg_offset() returns the offset to the register the argument specifies as indicated in an enumeration of type offset. Callers of this function would need the definition of such enumeration. This is not needed. Instead, add helper functions for this purpose. These functions are useful in cases when, for instance, the caller needs to decide whether the operand is a register or a memory location by looking at the rm part of the ModRM byte. As of now, this is the only helper function that is needed. Signed-off-by:
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Ricardo Neri authored
We are not in a critical failure path. The invalid register type is caused when trying to decode invalid instruction bytes from a user-space program. Thus, simply print an error message. To prevent this warning from being abused from user space programs, use the rate-limited variant of pr_err(). along with a descriptive prefix. Signed-off-by:
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Ricardo Neri authored
Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by:
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Ricardo Neri authored
Section 2.2.1.2 of the Intel 64 and IA-32 Architectures Software Developer's Manual volume 2A states that if a SIB byte is used and SIB.base is 101b and ModRM.mod is zero, then the base part of the base part of the effective address computation is null. To signal this situation, a -EDOM error is returned to indicate callers to ignore the base value present in the register operand. In this scenario, a 32-bit displacement follows the SIB byte. Displacement is obtained when the instruction decoder parses the operands. Signed-off-by:
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Ricardo Neri authored
Section 2.2.1.2 of the Intel 64 and IA-32 Architectures Software Developer's Manual volume 2A states that when ModRM.mod !=11b and ModRM.rm = 100b indexed register-indirect addressing is used. In other words, a SIB byte follows the ModRM byte. In the specific case of SIB.index = 100b, the scale*index portion of the computation of the effective address is null. To signal callers of this particular situation, get_reg_offset() can return -EDOM (-EINVAL continues to indicate that an error when decoding the SIB byte). An example of this situation can be the following instruction: 8b 4c 23 80 mov -0x80(%rbx,%riz,1),%rcx ModRM: 0x4c [mod:1b][reg:1b][rm:100b] SIB: 0x23 [scale:0b][index:100b][base:11b] Displacement: 0x80 (1-byte, as per ModRM.mod = 1b) The %riz 'register' indicates a null index. In long mode, a REX prefix may be used. When a REX prefix is present, REX.X adds a fourth bit to the register selection of SIB.index. This gives the ability to refer to all the 16 general purpose registers. When REX.X is 1b and SIB.index is 100b, the index is indicated in %r12. In our example, this would look like: 42 8b 4c 23 80 mov -0x80(%rbx,%r12,1),%rcx REX: 0x42 [W:0b][R:0b][X:1b][B:0b] ModRM: 0x4c [mod:1b][reg:1b][rm:100b] SIB: 0x23 [scale:0b][.X: 1b, index:100b][.B:0b, base:11b] Displacement: 0x80 (1-byte, as per ModRM.mod = 1b) %r12 is a valid register to use in the scale*index part of the effective address computation. Signed-off-by:
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Ricardo Neri authored
Even though memory addresses are unsigned, the operands used to compute the effective address do have a sign. This is true for ModRM.rm, SIB.base, SIB.index as well as the displacement bytes. Thus, signed variables shall be used when computing the effective address from these operands. Once the signed effective address has been computed, it is casted to an unsigned long to determine the linear address. Variables are renamed to better reflect the type of address being computed. Signed-off-by:
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Ricardo Neri authored
When errors occur in the computation of the linear address, -1L is returned. Rather than having a separate return path for errors, the variable used to return the computed linear address can be initialized with the error value. Hence, only one return path is needed. This makes the function easier to read. While here, ensure that the error value is -1L, a 64-bit value, rather than -1, a 32-bit value. Suggested-by:
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Ricardo Neri authored
Rather than using hard-coded values of the segment override prefixes, leverage the existing definitions provided in inat.h. Suggested-by:
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Ricardo Neri authored
In its current form, user_64bit_mode() can only be used when CONFIG_X86_64 is selected. This implies that code built with CONFIG_X86_64=n cannot use it. If a piece of code needs to be built for both CONFIG_X86_64=y and CONFIG_X86_64=n and wants to use this function, it needs to wrap it in an #ifdef/#endif; potentially, in multiple places. This can be easily avoided with a single #ifdef/#endif pair within user_64bit_mode() itself. Suggested-by:
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Ricardo Neri authored
Both head_32.S and head_64.S utilize the same value to initialize the control register CR0. Also, other parts of the kernel might want to access this initial definition (e.g., emulation code for User-Mode Instruction Prevention uses this state to provide a sane dummy value for CR0 when emulating the smsw instruction). Thus, relocate this definition to a header file from which it can be conveniently accessed. Suggested-by:
Borislav Petkov <bp@alien8.de> Signed-off-by:
Andy Lutomirski <luto@kernel.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: linux-mm@kvack.org Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Shuah Khan <shuah@kernel.org> Cc: linux-arch@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/1509135945-13762-3-git-send-email-ricardo.neri-calderon@linux.intel.com
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Ricardo Neri authored
Up to this point, only fault.c used the definitions of the page fault error codes. Thus, it made sense to keep them within such file. Other portions of code might be interested in those definitions too. For instance, the User- Mode Instruction Prevention emulation code will use such definitions to emulate a page fault when it is unable to successfully copy the results of the emulated instructions to user space. While relocating the error code enumeration, the prefix X86_ is used to make it consistent with the rest of the definitions in traps.h. Of course, code using the enumeration had to be updated as well. No functional changes were performed. Signed-off-by:
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- 31 Oct, 2017 1 commit
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Leon Romanovsky authored
IB device index is nldev's handler and it should be checked always. Fixes: c3f66f7b ("RDMA/netlink: Implement nldev port doit callback") Signed-off-by:
Leon Romanovsky <leonro@mellanox.com> Acked-by:
Doug Ledford <dledford@redhat.com> [ Applying directly, since Doug fried his SSD's and is rebuilding - Linus ] Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- 30 Oct, 2017 5 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pmLinus Torvalds authored
Pull power management fix from Rafael Wysocki: "This fixes new breakage introduced by the most recent PM QoS fix in which, embarrassingly enough, I forgot to update dev_pm_qos_raw_read_value() to return the right default for devices with no PM QoS constraints at all which prevents runtime PM from suspending those devices (fix from Tero Kristo)" * tag 'pm-urgent-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / QoS: Fix default runtime_pm device resume latency
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Linus Torvalds authored
It turns out that some drivers seem to think it's ok to remap page ranges from within interrupts and even NMI's. That is definitely not the case, since the page table build-up is simply not interrupt-safe. This showed up in the zero-day robot that reported it for the ACPI APEI GHES ("Generic Hardware Error Source") driver. Normally it had been hidden by the fact that no page table operations had been needed because the vmalloc area had been set up by other things. Apparently due to a recent change to the GHEI driver: commit 77b246b3 ("acpi: apei: check for pending errors when probing GHES entries") 0day actually caught a case during bootup whenthe ioremap called down to page allocation. But that recent change only showed the symptom, it wasn't the root cause of the problem. Hopefully it is limited to just that one driver. If you need to access random physical memory, you either need to ioremap in process context, or you need to use the FIXMAP facility to set one particular fixmap entry to the required mapping - that can be done safely. Cc: Borislav Petkov <bp@suse.de> Cc: Len Brown <lenb@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Tyler Baicar <tbaicar@codeaurora.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: -
git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmcLinus Torvalds authored
Pull MMC fixes from Ulf Hansson: "A couple of MMC host fixes intended for v4.14-rc8: - renesas_sdhi: fix kernel panic - tmio: fix swiotlb buffer is full" * tag 'mmc-v4.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: mmc: renesas_sdhi: fix kernel panic in _internal_dmac.c mmc: tmio: fix swiotlb buffer is full
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds authored
Pull crypto fix from Herbert Xu: "This fixes an objtool regression" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: x86/chacha20 - satisfy stack validation 2.0
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Tero Kristo authored
The recent change to the PM QoS framework to introduce a proper no constraint value overlooked to handle the devices which don't implement PM QoS OPS. Runtime PM is one of the more severely impacted subsystems, failing every attempt to runtime suspend a device. This leads into some nasty second level issues like probe failures and increased power consumption among other things. Fix this by adding a proper return value for devices that don't implement PM QoS. Fixes: 0cc2b4e5 (PM / QoS: Fix device resume latency PM QoS) Signed-off-by:
Tero Kristo <t-kristo@ti.com> Cc: All applicable <stable@vger.kernel.org> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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- 29 Oct, 2017 20 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds authored
Pull networking fixes from David Miller: 1) Fix route leak in xfrm_bundle_create(). 2) In mac80211, validate user rate mask before configuring it. From Johannes Berg. 3) Properly enforce memory limits in fair queueing code, from Toke Hoiland-Jorgensen. 4) Fix lockdep splat in inet_csk_route_req(), from Eric Dumazet. 5) Fix TSO header allocation and management in mvpp2 driver, from Yan Markman. 6) Don't take socket lock in BH handler in strparser code, from Tom Herbert. 7) Don't show sockets from other namespaces in AF_UNIX code, from Andrei Vagin. 8) Fix double free in error path of tap_open(), from Girish Moodalbail. 9) Fix TX map failure path in igb and ixgbe, from Jean-Philippe Brucker and Alexander Duyck. 10) Fix DCB mode programming in stmmac driver, from Jose Abreu. 11) Fix err_count handling in various tunnels (ipip, ip6_gre). From Xin Long. 12) Properly align SKB head before building SKB in tuntap, from Jason Wang. 13) Avoid matching qdiscs with a zero handle during lookups, from Cong Wang. 14) Fix various endianness bugs in sctp, from Xin Long. 15) Fix tc filter callback races and add selftests which trigger the problem, from Cong Wang. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (73 commits) selftests: Introduce a new test case to tc testsuite selftests: Introduce a new script to generate tc batch file net_sched: fix call_rcu() race on act_sample module removal net_sched: add rtnl assertion to tcf_exts_destroy() net_sched: use tcf_queue_work() in tcindex filter net_sched: use tcf_queue_work() in rsvp filter net_sched: use tcf_queue_work() in route filter net_sched: use tcf_queue_work() in u32 filter net_sched: use tcf_queue_work() in matchall filter net_sched: use tcf_queue_work() in fw filter net_sched: use tcf_queue_work() in flower filter net_sched: use tcf_queue_work() in flow filter net_sched: use tcf_queue_work() in cgroup filter net_sched: use tcf_queue_work() in bpf filter net_sched: use tcf_queue_work() in basic filter net_sched: introduce a workqueue for RCU callbacks of tc filter sctp: fix some type cast warnings introduced since very beginning sctp: fix a type cast warnings that causes a_rwnd gets the wrong value sctp: fix some type cast warnings introduced by transport rhashtable sctp: fix some type cast warnings introduced by stream reconf ... -
David S. Miller authored
Cong Wang says: ==================== net_sched: fix races with RCU callbacks Recently, the RCU callbacks used in TC filters and TC actions keep drawing my attention, they introduce at least 4 race condition bugs: 1. A simple one fixed by Daniel: commit c78e1746 Author: Daniel Borkmann <daniel@iogearbox.net> Date: Wed May 20 17:13:33 2015 +0200 net: sched: fix call_rcu() race on classifier module unloads 2. A very nasty one fixed by me: commit 1697c4bb Author: Cong Wang <xiyou.wangcong@gmail.com> Date: Mon Sep 11 16:33:32 2017 -0700 net_sched: carefully handle tcf_block_put() 3. Two more bugs found by Chris: https://patchwork.ozlabs.org/patch/826696/ https://patchwork.ozlabs.org/patch/826695/ Usually RCU callbacks are simple, however for TC filters and actions, they are complex because at least TC actions could be destroyed together with the TC filter in one callback. And RCU callbacks are invoked in BH context, without locking they are parallel too. All of these contribute to the cause of these nasty bugs. Alternatively, we could also: a) Introduce a spinlock to serialize these RCU callbacks. But as I said in commit 1697c4bb ("net_sched: carefully handle tcf_block_put()"), it is very hard to do because of tcf_chain_dump(). Potentially we need to do a lot of work to make it possible (if not impossible). b) Just get rid of these RCU callbacks, because they are not necessary at all, callers of these call_rcu() are all on slow paths and holding RTNL lock, so blocking is allowed in their contexts. However, David and Eric dislike adding synchronize_rcu() here. As suggested by Paul, we could defer the work to a workqueue and gain the permission of holding RTNL again without any performance impact, however, in tcf_block_put() we could have a deadlock when flushing workqueue while hodling RTNL lock, the trick here is to defer the work itself in workqueue and make it queued after all other works so that we keep the same ordering to avoid any use-after-free. Please see the first patch for details. Patch 1 introduces the infrastructure, patch 2~12 move each tc filter to the new tc filter workqueue, patch 13 adds an assertion to catch potential bugs like this, patch 14 closes another rcu callback race, patch 15 and patch 16 add new test cases. ==================== Reported-by:
Chris Mi <chrism@mellanox.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Chris Mi authored
In this patchset, we fixed a tc bug. This patch adds the test case that reproduces the bug. To run this test case, user should specify an existing NIC device: # sudo ./tdc.py -d enp4s0f0 This test case belongs to category "flower". If user doesn't specify a NIC device, the test cases belong to "flower" will not be run. In this test case, we create 1M filters and all filters share the same action. When destroying all filters, kernel should not panic. It takes about 18s to run it. Acked-by:
Jamal Hadi Salim <jhs@mojatatu.com> Acked-by:
Lucas Bates <lucasb@mojatatu.com> Signed-off-by:
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Chris Mi authored
# ./tdc_batch.py -h usage: tdc_batch.py [-h] [-n NUMBER] [-o] [-s] [-p] device file TC batch file generator positional arguments: device device name file batch file name optional arguments: -h, --help show this help message and exit -n NUMBER, --number NUMBER how many lines in batch file -o, --skip_sw skip_sw (offload), by default skip_hw -s, --share_action all filters share the same action -p, --prio all filters have different prio Acked-by: -
Cong Wang authored
Similar to commit c78e1746 ("net: sched: fix call_rcu() race on classifier module unloads"), we need to wait for flying RCU callback tcf_sample_cleanup_rcu(). Cc: Yotam Gigi <yotamg@mellanox.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by:
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Cong Wang authored
After previous patches, it is now safe to claim that tcf_exts_destroy() is always called with RTNL lock. Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by:
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Cong Wang authored
This patch introduces a dedicated workqueue for tc filters so that each tc filter's RCU callback could defer their action destroy work to this workqueue. The helper tcf_queue_work() is introduced for them to use. Because we hold RTNL lock when calling tcf_block_put(), we can not simply flush works inside it, therefore we have to defer it again to this workqueue and make sure all flying RCU callbacks have already queued their work before this one, in other words, to ensure this is the last one to execute to prevent any use-after-free. On the other hand, this makes tcf_block_put() ugly and harder to understand. Since David and Eric strongly dislike adding synchronize_rcu(), this is probably the only solution that could make everyone happy. Please also see the code comments below. Reported-by:
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David S. Miller authored
Xin Long says: ==================== sctp: a bunch of fixes for some sparse warnings As Eric noticed, when running 'make C=2 M=net/sctp/', a plenty of warnings or errors checked by sparse appear. They are all problems about Endian and type cast. Most of them are just warnings by which no issues could be caused while some might be bugs. This patchset fixes them with four patches basically according to how they are introduced. ==================== Signed-off-by:
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