- 15 May, 2019 40 commits
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Feng Tang authored
When kernel panic happens, it will first print the panic call stack, then the ending msg like: [ 35.743249] ---[ end Kernel panic - not syncing: Fatal exception [ 35.749975] ------------[ cut here ]------------ The above message are very useful for debugging. But if system is configured to not reboot on panic, say the "panic_timeout" parameter equals 0, it will likely print out many noisy message like WARN() call stack for each and every CPU except the panic one, messages like below: WARNING: CPU: 1 PID: 280 at kernel/sched/core.c:1198 set_task_cpu+0x183/0x190 Call Trace: <IRQ> try_to_wake_up default_wake_function autoremove_wake_function __wake_up_common __wake_up_common_lock __wake_up wake_up_klogd_work_func irq_work_run_list irq_work_tick update_process_times tick_sched_timer __hrtimer_run_queues hrtimer_interrupt smp_apic_timer_interrupt apic_timer_interrupt For people working in console mode, the screen will first show the panic call stack, but immediately overridden by these noisy extra messages, which makes debugging much more difficult, as the original context gets lost on screen. Also these noisy messages will confuse some users, as I have seen many bug reporters posted the noisy message into bugzilla, instead of the real panic call stack and context. Adding a flag "suppress_printk" which gets set in panic() to avoid those noisy messages, without changing current kernel behavior that both panic blinking and sysrq magic key can work as is, suggested by Petr Mladek. To verify this, make sure kernel is not configured to reboot on panic and in console # echo c > /proc/sysrq-trigger to see if console only prints out the panic call stack. Link: http://lkml.kernel.org/r/1551430186-24169-1-git-send-email-feng.tang@intel.comSigned-off-by:
Feng Tang <feng.tang@intel.com> Suggested-by:
Petr Mladek <pmladek@suse.com> Reviewed-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kees Cook <keescook@chromium.org> Cc: Borislav Petkov <bp@suse.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Greg Hackmann authored
LLVM uses profiling data that's deliberately similar to GCC, but has a very different way of exporting that data. LLVM calls llvm_gcov_init() once per module, and provides a couple of callbacks that we can use to ask for more data. We care about the "writeout" callback, which in turn calls back into compiler-rt/this module to dump all the gathered coverage data to disk: llvm_gcda_start_file() llvm_gcda_emit_function() llvm_gcda_emit_arcs() llvm_gcda_emit_function() llvm_gcda_emit_arcs() [... repeats for each function ...] llvm_gcda_summary_info() llvm_gcda_end_file() This design is much more stateless and unstructured than gcc's, and is intended to run at process exit. This forces us to keep some local state about which module we're dealing with at the moment. On the other hand, it also means we don't depend as much on how LLVM represents profiling data internally. See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more details on how this works, particularly GCOVProfiler::emitProfileArcs(), GCOVProfiler::insertCounterWriteout(), and GCOVProfiler::insertFlush(). [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190417225328.208129-1-trong@android.comSigned-off-by:Greg Hackmann <ghackmann@android.com> Signed-off-by:
Nick Desaulniers <ndesaulniers@google.com> Signed-off-by:
Tri Vo <trong@android.com> Co-developed-by:
Trilok Soni <tsoni@quicinc.com> Tested-by:
Prasad Sodagudi <psodagud@quicinc.com> Tested-by:
Daniel Mentz <danielmentz@google.com> Tested-by:
Petri Gynther <pgynther@google.com> Reviewed-by:
Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by:
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Tri Vo authored
Document some things of note to gcov users: 1. GCC gcov and Clang llvm-cov tools are not compatible. 2. The use of GCC vs Clang is transparent at build-time. Also adjust the documentation to account for the removal of config symbol CONFIG_GCOV_FORMAT_AUTODETECT by commit 6a61b70b ("gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT"). Link: http://lkml.kernel.org/r/20190318025411.98014-4-trong@android.comSigned-off-by:
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Greg Hackmann authored
Patch series "gcov: add Clang support", v4. This patch (of 3): base.c contains a few callbacks specific to GCC's gcov implementation. Move these into their own module in preparation for Clang support. Link: http://lkml.kernel.org/r/20190318025411.98014-2-trong@android.comSigned-off-by:
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YueHaibing authored
Fix sparse warning: fs/eventfd.c:26:1: warning: symbol 'eventfd_ida' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20190413142348.34716-1-yuehaibing@huawei.comSigned-off-by:
YueHaibing <yuehaibing@huawei.com> Signed-off-by:
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Masatake YAMATO authored
Finding endpoints of an IPC channel is one of essential task to understand how a user program works. Procfs and netlink socket provide enough hints to find endpoints for IPC channels like pipes, unix sockets, and pseudo terminals. However, there is no simple way to find endpoints for an eventfd file from userland. An inode number doesn't hint. Unlike pipe, all eventfd files share the same inode object. To provide the way to find endpoints of an eventfd file, this patch adds "eventfd-id" field to /proc/PID/fdinfo of eventfd as identifier. Integers managed by an IDA are used as ids. A tool like lsof can utilize the information to print endpoints. Link: http://lkml.kernel.org/r/20190327181823.20222-1-yamato@redhat.comSigned-off-by:
Masatake YAMATO <yamato@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
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Timmy Li authored
Hash functions are not needed since idr is used now. Let's remove hash header file for cleanup. Link: http://lkml.kernel.org/r/20190430053319.95913-1-scuttimmy@gmail.comSigned-off-by:
Timmy Li <scuttimmy@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: KJ Tsanaktsidis <ktsanaktsidis@zendesk.com> Signed-off-by:
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Eric Sandeen authored
Today, proc_do_large_bitmap() truncates a large write input buffer to PAGE_SIZE - 1, which may result in misparsed numbers at the (truncated) end of the buffer. Further, it fails to notify the caller that the buffer was truncated, so it doesn't get called iteratively to finish the entire input buffer. Tell the caller if there's more work to do by adding the skipped amount back to left/*lenp before returning. To fix the misparsing, reset the position if we have completely consumed a truncated buffer (or if just one char is left, which may be a "-" in a range), and ask the caller to come back for more. Link: http://lkml.kernel.org/r/20190320222831.8243-7-mcgrof@kernel.orgSigned-off-by:
Eric Sandeen <sandeen@redhat.com> Signed-off-by:
Luis Chamberlain <mcgrof@kernel.org> Acked-by:
Kees Cook <keescook@chromium.org> Cc: Eric Sandeen <sandeen@sandeen.net> Signed-off-by:
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Eric Sandeen authored
The kernel has only two users of proc_do_large_bitmap(), the kernel CPU watchdog, and the ip_local_reserved_ports. Refer to watchdog_cpumask and ip_local_reserved_ports in Documentation for further details on these. When you input a large buffer into these, when it is larger than PAGE_SIZE- 1, the input data gets misparsed, and the user get incorrectly informed that the desired input value was set. This commit implements a test which mimics and exploits that use case, it uses a bitmap size, as in the watchdog case. The bitmap is used to test the bitmap proc handler, proc_do_large_bitmap(). The next commit fixes this issue. [akpm@linux-foundation.org: move proc_do_large_bitmap() export to EOF] [mcgrof@kernel.org: use new target description for backward compatibility] [mcgrof@kernel.org: augment test number to 50, ran into issues with bash string comparisons when testing up to 50 cases.] [mcgrof@kernel.org: introduce and use verify_diff_proc_file() to use diff] [mcgrof@kernel.org: use mktemp for tmp file] [mcgrof@kernel.org: merge shell test and C code] [mcgrof@kernel.org: commit log love] [mcgrof@kernel.org: export proc_do_large_bitmap() to allow for the test [mcgrof@kernel.org: check for the return value when writing to the proc file] Link: http://lkml.kernel.org/r/20190320222831.8243-6-mcgrof@kernel.orgSigned-off-by:
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Luis Chamberlain authored
On old kernels older new test knobs implemented on the test_sysctl module may not be available. This is expected, and the selftests test scripts should be able to run without failures on older kernels. Generalize a solution so that we test for each required test target file for each test by requiring each test description to annotate their respective test target file. If the target file does not exist, we skip the test gracefully. Link: http://lkml.kernel.org/r/20190320222831.8243-5-mcgrof@kernel.orgSigned-off-by:
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Luis Chamberlain authored
When verify_diff_w() is used we care about the result, not the verbose output, and although we use -q, that still gives us a chatty message about if the files differ or not. Since verify_diff_w() uses stdinput the chatty message says whether or not "-" matches the target file, and this just seems rather odd. Better to just ignore that messsage all together, what we really care about i sthe results, the return value and we check for that. Link: http://lkml.kernel.org/r/20190320222831.8243-4-mcgrof@kernel.orgSigned-off-by:
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Luis Chamberlain authored
Currently the test script checks for the existence of the sysctl test module's directory path prior to loading it. We must first try to load the module prior to checking for that path. This fixes the order for the load / test. Link: http://lkml.kernel.org/r/20190320222831.8243-3-mcgrof@kernel.orgSigned-off-by:
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Luis Chamberlain authored
Patch series "sysctl: add pending proc_do_large_bitmap fix". Eric sent a fix out for proc_do_large_bitmap() last month for when using a large input buffer. After patch review a test case for the issue was built and submitted. I noticed there were a few issues with the tests, but instead of just asking Eric to address them I've taken care of them and ammended the commit where necessary. There's a few issues he reported which I also address and fix in this series. Since we *do* expect users of these scripts to also use them on older kernels, I've also addressed not breaking calling the script for them, and gives us an easy way to easily extend our tests cases for future kernels as well. Before anyone considers these for stable as minor fixes, I'd recommend we also address the discrepancy on the read side of things: modify the test script to use diff against the target file instead of using the temp file. This patch (of 6): We already call test_reqs(), no need to call it twice. Link: http://lkml.kernel.org/r/20190320222831.8243-2-mcgrof@kernel.orgSigned-off-by:
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Christian Brauner authored
Currently when userspace gives us a values that overflow e.g. file-max and other callers of __do_proc_doulongvec_minmax() we simply ignore the new value and leave the current value untouched. This can be problematic as it gives the illusion that the limit has indeed be bumped when in fact it failed. This commit makes sure to return EINVAL when an overflow is detected. Please note that this is a userspace facing change. Link: http://lkml.kernel.org/r/20190210203943.8227-4-christian@brauner.ioSigned-off-by:
Christian Brauner <christian@brauner.io> Acked-by:
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Andy Shevchenko authored
Switch to bitmap_zalloc() to show clearly what we are allocating. Besides that it returns pointer of bitmap type instead of opaque void *. Link: http://lkml.kernel.org/r/20190304094037.57756-1-andriy.shevchenko@linux.intel.comSigned-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by:
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Kangjie Lu authored
In case create_workqueue fails, the fix releases resources and returns -ENOMEM to avoid NULL pointer dereference. Signed-off-by:
Kangjie Lu <kjlu@umn.edu> Acked-by:
Alexandre Bounine <alex.bou9@gmail.com> Cc: Matt Porter <mporter@kernel.crashing.org> Signed-off-by:
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Yury Norov authored
cpumask_parse() finds first occurrence of either or strchr() and strlen(). We can do it better with a single call of strchrnul(). [akpm@linux-foundation.org: remove unneeded cast] Link: http://lkml.kernel.org/r/20190409204208.12190-1-ynorov@marvell.comSigned-off-by:
Yury Norov <ynorov@marvell.com> Acked-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Alexey Dobriyan authored
Test that trivially recursing script onto itself doesn't work. Note: this is different test from ELOOP tests in execveat.c Those test that execveat(2) doesn't follow symlinks when told to do so. Link: http://lkml.kernel.org/r/20190423192720.GA21433@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
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Alexey Dobriyan authored
struct linux_binprm::buf is the first field and it is exactly 128 bytes in size. It means that on x86_64 all accesses to other fields will go though [r64 + disp32] addressing mode which is 3 bytes bloatier than [r64 + disp8] addressing mode. Given that accesses to other fields outnumber accesses to ->buf, move it down. Space savings (x86_64 defconfig): more on distro configs because LSMs actively dereference "bprm" but do not care about first 128 bytes of the executable itself. add/remove: 0/0 grow/shrink: 0/24 up/down: 0/-492 (-492) Function old new delta selinux_bprm_committing_creds 552 549 -3 finalize_exec 94 91 -3 __audit_log_bprm_fcaps 283 280 -3 __audit_bprm 39 36 -3 perf_trace_sched_process_exec 347 341 -6 install_exec_creds 105 99 -6 cap_bprm_set_creds.cold 60 54 -6 would_dump 137 128 -9 load_script 637 628 -9 bprm_change_interp 61 52 -9 trace_event_raw_event_sched_process_exec 260 250 -10 search_binary_handler 255 240 -15 remove_arg_zero 295 277 -18 free_bprm 119 101 -18 prepare_binprm 379 360 -19 setup_new_exec 336 315 -21 flush_old_exec 1638 1617 -21 copy_strings.isra 746 724 -22 setup_arg_pages 559 530 -29 load_misc_binary 1151 1118 -33 selinux_bprm_set_creds 792 753 -39 load_elf_binary 11111 11072 -39 cap_bprm_set_creds 1496 1454 -42 __do_execve_file.isra 2395 2286 -109 Link: http://lkml.kernel.org/r/20190421165025.GA26843@avx2Signed-off-by:
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Alexey Dobriyan authored
->recursion_depth is changed only by current, therefore decrementing can be done without taking any locks. Link: http://lkml.kernel.org/r/20190417213150.GA26474@avx2Signed-off-by:
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Mathieu Malaterre authored
There is a plan to build the kernel with -Wimplicit-fallthrough and this place in the code produced a warning (W=1). This commit remove the following warning: kernel/signal.c:795:13: warning: this statement may fall through [-Wimplicit-fallthrough=] Link: http://lkml.kernel.org/r/20190114203505.17875-1-malat@debian.orgSigned-off-by:
Mathieu Malaterre <malat@debian.org> Acked-by:
Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by:
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Hou Tao authored
fsync() needs to make sure the data & meta-data of file are persistent after the return of fsync(), even when a power-failure occurs later. In the case of fat-fs, the FAT belongs to the meta-data of file, so we need to issue a flush after the writeback of FAT instead before. Also bail out early when any stage of fsync fails. Link: http://lkml.kernel.org/r/20190409030158.136316-1-houtao1@huawei.comSigned-off-by:
Hou Tao <houtao1@huawei.com> Acked-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jan Kara <jack@suse.cz> Signed-off-by:
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Bharath Vedartham authored
csum_partial() gives different results for little-endian and big-endian hosts. This causes images created on little-endian hosts and mounted on big endian hosts to see csum mismatches. This causes an endianness bug. Sparse gives a warning as csum_partial returns a restricted integer type __wsum_t and xattr_hash expects __u32. This warning acts as a reminder for this bug and should not be suppressed. This comment aims to convey these endianness issues. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190423161831.GA15387@bharath12345-Inspiron-5559Signed-off-by:
Bharath Vedartham <linux.bhar@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jann Horn <jannh@google.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by:
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Ian Kent authored
Add a description of the "ignore" pseudo mount option that can be used to provide a generic indicator to applications that the mount entry should be ignored when displaying mount information. Link: http://lkml.kernel.org/r/155287084617.12593.812733161112154904.stgit@pluto.themaw.netSigned-off-by:
Ian Kent <raven@themaw.net> Signed-off-by:
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Ian Kent authored
Describe AUTOFS_EXP_FORCED in addition to AUTOFS_EXP_IMMEDIATE in the description of the AUTOFS_DEV_IOCTL_EXPIRE_CMD ioctl. Link: http://lkml.kernel.org/r/155287084078.12593.15000931045413195778.stgit@pluto.themaw.netSigned-off-by:
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Ian Kent authored
Update the description of AUTOFS_EXP_LEAVES to cover its possible future use with amd format mount maps. Link: http://lkml.kernel.org/r/155287083538.12593.18163159677020718048.stgit@pluto.themaw.netSigned-off-by:
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Ian Kent authored
A "strictexpire" mount option has been added to the autofs file system. It is meant to be used in cases where a GUI continually accesses or an application frquently scans an automount directory tree causing an accumulation of otherwise unused mounts. Link: http://lkml.kernel.org/r/155287083000.12593.2722713092537666885.stgit@pluto.themaw.netSigned-off-by:
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Ian Kent authored
Alter a few word usages in Documentation/filesystems/autofs.txt and correct some spelling mistakes. Link: http://lkml.kernel.org/r/155287082394.12593.6506084453911662450.stgit@pluto.themaw.netSigned-off-by:
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Sinan Kaya authored
CONFIG_DEBUG_KERNEL should not impact code generation. Use the newly defined CONFIG_DEBUG_MISC instead to keep the current code. Link: http://lkml.kernel.org/r/20190413224438.10802-6-okaya@kernel.orgSigned-off-by:
Sinan Kaya <okaya@kernel.org> Acked-by:
Florian Westphal <fw@strlen.de> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> Reviewed-by:
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Sinan Kaya authored
CONFIG_DEBUG_KERNEL should not impact code generation. Use the newly defined CONFIG_DEBUG_MISC instead to keep the current code. Link: http://lkml.kernel.org/r/20190413224438.10802-5-okaya@kernel.orgSigned-off-by:
Max Filippov <jcmvbkbc@gmail.com> Cc: Chris Zankel <chris@zankel.net> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: "David S. Miller" <davem@davemloft.net> Cc: Florian Westphal <fw@strlen.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: James Hogan <jhogan@kernel.org> Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by:
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Sinan Kaya authored
CONFIG_DEBUG_KERNEL should not impact code generation. Use the newly defined CONFIG_DEBUG_MISC instead to keep the current code. Link: http://lkml.kernel.org/r/20190413224438.10802-3-okaya@kernel.orgSigned-off-by:
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Sinan Kaya authored
Patch series "init: Do not select DEBUG_KERNEL by default", v5. CONFIG_DEBUG_KERNEL has been designed to just enable Kconfig options. Kernel code generatoin should not depend on CONFIG_DEBUG_KERNEL. Proposed alternative plan: let's add a new symbol, something like DEBUG_MISC ("Miscellaneous debug code that should be under a more specific debug option but isn't"), make it depend on DEBUG_KERNEL and be "default DEBUG_KERNEL" but allow itself to be turned off, and then mechanically change the small handful of "#ifdef CONFIG_DEBUG_KERNEL" to "#ifdef CONFIG_DEBUG_MISC". This patch (of 5): Introduce DEBUG_MISC ("Miscellaneous debug code that should be under a more specific debug option but isn't"), make it depend on DEBUG_KERNEL and be "default DEBUG_KERNEL" but allow itself to be turned off, and then mechanically change the small handful of "#ifdef CONFIG_DEBUG_KERNEL" to "#ifdef CONFIG_DEBUG_MISC". Link: http://lkml.kernel.org/r/20190413224438.10802-2-okaya@kernel.orgSigned-off-by: -
Kees Cook authored
Commmit eab09532 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE"), made changes in the rare case when the ELF loader was directly invoked (e.g to set a non-inheritable LD_LIBRARY_PATH, testing new versions of the loader), by moving into the mmap region to avoid both ET_EXEC and PIE binaries. This had the effect of also moving the brk region into mmap, which could lead to the stack and brk being arbitrarily close to each other. An unlucky process wouldn't get its requested stack size and stack allocations could end up scribbling on the heap. This is illustrated here. In the case of using the loader directly, brk (so helpfully identified as "[heap]") is allocated with the _loader_ not the binary. For example, with ASLR entirely disabled, you can see this more clearly: $ /bin/cat /proc/self/maps 555555554000-55555555c000 r-xp 00000000 ... /bin/cat 55555575b000-55555575c000 r--p 00007000 ... /bin/cat 55555575c000-55555575d000 rw-p 00008000 ... /bin/cat 55555575d000-55555577e000 rw-p 00000000 ... [heap] ... 7ffff7ff7000-7ffff7ffa000 r--p 00000000 ... [vvar] 7ffff7ffa000-7ffff7ffc000 r-xp 00000000 ... [vdso] 7ffff7ffc000-7ffff7ffd000 r--p 00027000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffd000-7ffff7ffe000 rw-p 00028000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffe000-7ffff7fff000 rw-p 00000000 ... 7ffffffde000-7ffffffff000 rw-p 00000000 ... [stack] $ /lib/x86_64-linux-gnu/ld-2.27.so /bin/cat /proc/self/maps ... 7ffff7bcc000-7ffff7bd4000 r-xp 00000000 ... /bin/cat 7ffff7bd4000-7ffff7dd3000 ---p 00008000 ... /bin/cat 7ffff7dd3000-7ffff7dd4000 r--p 00007000 ... /bin/cat 7ffff7dd4000-7ffff7dd5000 rw-p 00008000 ... /bin/cat 7ffff7dd5000-7ffff7dfc000 r-xp 00000000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7fb2000-7ffff7fd6000 rw-p 00000000 ... 7ffff7ff7000-7ffff7ffa000 r--p 00000000 ... [vvar] 7ffff7ffa000-7ffff7ffc000 r-xp 00000000 ... [vdso] 7ffff7ffc000-7ffff7ffd000 r--p 00027000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffd000-7ffff7ffe000 rw-p 00028000 ... /lib/x86_64-linux-gnu/ld-2.27.so 7ffff7ffe000-7ffff8020000 rw-p 00000000 ... [heap] 7ffffffde000-7ffffffff000 rw-p 00000000 ... [stack] The solution is to move brk out of mmap and into ELF_ET_DYN_BASE since nothing is there in the direct loader case (and ET_EXEC is still far away at 0x400000). Anything that ran before should still work (i.e. the ultimately-launched binary already had the brk very far from its text, so this should be no different from a COMPAT_BRK standpoint). The only risk I see here is that if someone started to suddenly depend on the entire memory space lower than the mmap region being available when launching binaries via a direct loader execs which seems highly unlikely, I'd hope: this would mean a binary would _not_ work when exec()ed normally. (Note that this is only done under CONFIG_ARCH_HAS_ELF_RANDOMIZATION when randomization is turned on.) Link: http://lkml.kernel.org/r/20190422225727.GA21011@beast Link: https://lkml.kernel.org/r/CAGXu5jJ5sj3emOT2QPxQkNQk0qbU6zEfu9=Omfhx_p0nCKPSjA@mail.gmail.com Fixes: eab09532 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE") Signed-off-by:
Ali Saidi <alisaidi@amazon.com> Cc: Ali Saidi <alisaidi@amazon.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jann Horn <jannh@google.com> Signed-off-by:
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Alexey Dobriyan authored
Get "current_pt_regs" pointer right before usage. Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-180 (-180) Function old new delta load_elf_binary 5806 5626 -180 !!! Looks like the compiler doesn't know that "current_pt_regs" is stable pointer (because it doesn't know ->stack isn't) even though it knows that "current" is stable pointer. So it saves it in the very beginning and then tries to carry it through a lot of code. Here is what happens here: load_elf_binary() ... mov rax,QWORD PTR gs:0x14c00 mov r13,QWORD PTR [rax+0x18] r13 = current->stack call kmem_cache_alloc # first kmalloc [980 bytes later!] # let's spill that sucker because we need a register # for "load_bias" calculations at # # if (interpreter) { # load_bias = ELF_ET_DYN_BASE; # if (current->flags & PF_RANDOMIZE) # load_bias += arch_mmap_rnd(); # elf_flags |= elf_fixed; # } mov QWORD PTR [rsp+0x68],r13 If this is not _the_ root cause it is still eeeeh. After the patch things become much simpler: mov rax, QWORD PTR gs:0x14c00 # current mov rdx, QWORD PTR [rax+0x18] # current->stack movq [rdx+0x3fb8], 0 # fill pt_regs ... call finalize_exec Link: http://lkml.kernel.org/r/20190419200343.GA19788@avx2Signed-off-by: -
Alexey Dobriyan authored
There are two places where mapping protections are calculated: one for executable, another one for interpreter -- take them out. ELF read and execute permissions are interchanged with Linux PROT_READ and PROT_EXEC, microoptimizations are welcome! Link: http://lkml.kernel.org/r/20190417213413.GB26474@avx2Signed-off-by:
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Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20190416202002.GB24304@avx2Signed-off-by:
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Alexey Dobriyan authored
Rewrite for (...) { if (->p_type == PT_INTERP) { ... break; } } loop into for (...) { if (->p_type != PT_INTERP) continue; ... break; } Link: http://lkml.kernel.org/r/20190416201906.GA24304@avx2Signed-off-by: -
Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20190314205042.GE18143@avx2Signed-off-by:
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Alexey Dobriyan authored
There is no reason for PT_INTERP filename to linger till the end of the whole loading process. Link: http://lkml.kernel.org/r/20190314204953.GD18143@avx2Signed-off-by:
Nikitas Angelinas <nikitas.angelinas@gmail.com> Reviewed-by:
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Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20190314204707.GC18143@avx2Signed-off-by:
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