Building with function tracer fails #35

agners · 2018-09-10T19:57:29Z

Building ARM32 with function tracing enabled currently fails at linking stage:

  LD      vmlinux.o                                                     
                                                                  
  MODPOST vmlinux.o
kernel/softirq.o: In function `_local_bh_enable':
/home/ags/projects/toradex/imx/linux-vanilla-llvm/kernel/softirq.c:152:
undefined reference to `mcount'
kernel/softirq.o: In function `__local_bh_enable_ip':
/home/ags/projects/toradex/imx/linux-vanilla-llvm/kernel/softirq.c:159:
undefined reference to `mcount'
kernel/softirq.o: In function `do_softirq':
/home/ags/projects/toradex/imx/linux-vanilla-llvm/kernel/softirq.c:316:
undefined reference to `mcount'
kernel/softirq.o: In function `irq_enter':
/home/ags/projects/toradex/imx/linux-vanilla-llvm/kernel/softirq.c:337:
undefined reference to `mcount'
kernel/softirq.o: In function `irq_exit':
/home/ags/projects/toradex/imx/linux-vanilla-llvm/kernel/softirq.c:395:
undefined reference to `mcount'

The text was updated successfully, but these errors were encountered:

agners · 2018-09-10T20:00:08Z

Adding -meabi gnu allows to compile the kernel, however, it will crash silently on boot, see also:

https://lore.kernel.org/r/35ae3d464c7b77a5fe86a732079e32bc@agner.ch/

m-gupta · 2018-09-12T21:07:23Z

Use of "-pg" with "-meabi gnu" on ARM32 is currently known to be broken in clang :-(
https://llvm.org/pr33845

Increase kasan instrumented kernel stack size from 32k to 64k. Other architectures seems to get away with just doubling kernel stack size under kasan, but on s390 this appears to be not enough due to bigger frame size. The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting stack overflow is fs sync on xfs filesystem: #0 [9a0681e8] 704 bytes check_usage at 34b1fc #1 [9a0684a8] 432 bytes check_usage at 34c710 #2 [9a068658] 1048 bytes validate_chain at 35044a #3 [9a068a70] 312 bytes __lock_acquire at 3559fe #4 [9a068ba8] 440 bytes lock_acquire at 3576ee #5 [9a068d60] 104 bytes _raw_spin_lock at 21b44e0 #6 [9a068dc8] 1992 bytes enqueue_entity at 2dbf72 #7 [9a069590] 1496 bytes enqueue_task_fair at 2df5f0 #8 [9a069b68] 64 bytes ttwu_do_activate at 28f438 #9 [9a069ba8] 552 bytes try_to_wake_up at 298c4c #10 [9a069dd0] 168 bytes wake_up_worker at 23f97c #11 [9a069e78] 200 bytes insert_work at 23fc2e #12 [9a069f40] 648 bytes __queue_work at 2487c0 #13 [9a06a1c8] 200 bytes __queue_delayed_work at 24db28 #14 [9a06a290] 248 bytes mod_delayed_work_on at 24de84 #15 [9a06a388] 24 bytes kblockd_mod_delayed_work_on at 153e2a0 #16 [9a06a3a0] 288 bytes __blk_mq_delay_run_hw_queue at 158168c #17 [9a06a4c0] 192 bytes blk_mq_run_hw_queue at 1581a3c #18 [9a06a580] 184 bytes blk_mq_sched_insert_requests at 15a2192 #19 [9a06a638] 1024 bytes blk_mq_flush_plug_list at 1590f3a #20 [9a06aa38] 704 bytes blk_flush_plug_list at 1555028 #21 [9a06acf8] 320 bytes schedule at 219e476 #22 [9a06ae38] 760 bytes schedule_timeout at 21b0aac #23 [9a06b130] 408 bytes wait_for_common at 21a1706 #24 [9a06b2c8] 360 bytes xfs_buf_iowait at fa1540 #25 [9a06b430] 256 bytes __xfs_buf_submit at fadae6 #26 [9a06b530] 264 bytes xfs_buf_read_map at fae3f6 #27 [9a06b638] 656 bytes xfs_trans_read_buf_map at 10ac9a8 #28 [9a06b8c8] 304 bytes xfs_btree_kill_root at e72426 #29 [9a06b9f8] 288 bytes xfs_btree_lookup_get_block at e7bc5e #30 [9a06bb18] 624 bytes xfs_btree_lookup at e7e1a6 #31 [9a06bd88] 2664 bytes xfs_alloc_ag_vextent_near at dfa070 #32 [9a06c7f0] 144 bytes xfs_alloc_ag_vextent at dff3ca #33 [9a06c880] 1128 bytes xfs_alloc_vextent at e05fce #34 [9a06cce8] 584 bytes xfs_bmap_btalloc at e58342 #35 [9a06cf30] 1336 bytes xfs_bmapi_write at e618de #36 [9a06d468] 776 bytes xfs_iomap_write_allocate at ff678e #37 [9a06d770] 720 bytes xfs_map_blocks at f82af8 #38 [9a06da40] 928 bytes xfs_writepage_map at f83cd6 #39 [9a06dde0] 320 bytes xfs_do_writepage at f85872 #40 [9a06df20] 1320 bytes write_cache_pages at 73dfe8 #41 [9a06e448] 208 bytes xfs_vm_writepages at f7f892 #42 [9a06e518] 88 bytes do_writepages at 73fe6a #43 [9a06e570] 872 bytes __writeback_single_inode at a20cb6 #44 [9a06e8d8] 664 bytes writeback_sb_inodes at a23be2 #45 [9a06eb70] 296 bytes __writeback_inodes_wb at a242e0 #46 [9a06ec98] 928 bytes wb_writeback at a2500e #47 [9a06f038] 848 bytes wb_do_writeback at a260ae #48 [9a06f388] 536 bytes wb_workfn at a28228 #49 [9a06f5a0] 1088 bytes process_one_work at 24a234 #50 [9a06f9e0] 1120 bytes worker_thread at 24ba26 #51 [9a06fe40] 104 bytes kthread at 26545a #52 [9a06fea8] kernel_thread_starter at 21b6b62 To be able to increase the stack size to 64k reuse LLILL instruction in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE (65192) value as unsigned. Reported-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

agners · 2018-11-19T22:30:21Z

@m-gupta probably depends what the exact definition is of GNU mcount... I guess GCC is the ABI, and Clang/LLVM should follow. And yes, GCC pushes the lr to the stack, see also:

https://lore.kernel.org/r/71400574f8e914ee994c82564485b79e@agner.ch/

Clang creates the mcount calls in a Function pass in lib/Transforms/Utils/EntryExitInstrumenter.cpp. Afaik, this is at LLVM IR level, it is probably not easy to just insert a push {lr} there.

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

The armv8_pmuv3 driver doesn't have a remove function, and when the test 'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, the following Call trace can be seen. [ 1.424287] Failed to register pmu: armv8_pmuv3, reason -17 [ 1.424870] WARNING: CPU: 0 PID: 1 at ../kernel/events/core.c:11771 perf_event_sysfs_init+0x98/0xdc [ 1.425220] Modules linked in: [ 1.425531] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.19.0-rc7-next-20181012-00003-ge7a97b1ad77b-dirty #35 [ 1.425951] Hardware name: linux,dummy-virt (DT) [ 1.426212] pstate: 80000005 (Nzcv daif -PAN -UAO) [ 1.426458] pc : perf_event_sysfs_init+0x98/0xdc [ 1.426720] lr : perf_event_sysfs_init+0x98/0xdc [ 1.426908] sp : ffff00000804bd50 [ 1.427077] x29: ffff00000804bd50 x28: ffff00000934e078 [ 1.427429] x27: ffff000009546000 x26: 0000000000000007 [ 1.427757] x25: ffff000009280710 x24: 00000000ffffffef [ 1.428086] x23: ffff000009408000 x22: 0000000000000000 [ 1.428415] x21: ffff000009136008 x20: ffff000009408730 [ 1.428744] x19: ffff80007b20b400 x18: 000000000000000a [ 1.429075] x17: 0000000000000000 x16: 0000000000000000 [ 1.429418] x15: 0000000000000400 x14: 2e79726f74636572 [ 1.429748] x13: 696420656d617320 x12: 656874206e692065 [ 1.430060] x11: 6d616e20656d6173 x10: 2065687420687469 [ 1.430335] x9 : ffff00000804bd50 x8 : 206e6f7361657220 [ 1.430610] x7 : 2c3376756d705f38 x6 : ffff00000954d7ce [ 1.430880] x5 : 0000000000000000 x4 : 0000000000000000 [ 1.431226] x3 : 0000000000000000 x2 : ffffffffffffffff [ 1.431554] x1 : 4d151327adc50b00 x0 : 0000000000000000 [ 1.431868] Call trace: [ 1.432102] perf_event_sysfs_init+0x98/0xdc [ 1.432382] do_one_initcall+0x6c/0x1a8 [ 1.432637] kernel_init_freeable+0x1bc/0x280 [ 1.432905] kernel_init+0x18/0x160 [ 1.433115] ret_from_fork+0x10/0x18 [ 1.433297] ---[ end trace 27fd415390eb9883 ]--- Rework to set suppress_bind_attrs flag to avoid removing the device when CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, since there's no real reason to remove the armv8_pmuv3 driver. Cc: Arnd Bergmann <arnd@arndb.de> Co-developed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki · 2019-01-02T12:41:55Z

ppc64 be fails with the same error message:

  AR      built-in.a
  LD      vmlinux.o
  MODPOST vmlinux.o
powerpc64-linux-gnu-ld: init/do_mounts_initrd.o:(__mcount_loc+0x0): undefined reference to `.init_linuxrc'

https://travis-ci.org/shenki/continuous-integration/jobs/474371134#L2813

It can be worked around by disabling ftrace.

nathanchance · 2019-02-15T03:59:01Z

FWIW, this, #325 (when using ld.bfd), and #17 (which has patches posted upstream) are the only three issues that prevent successfully building arm allyesconfig on linux-next (and I assume allmodconfig but I haven't tried). I have been working around it with the following patch, I wonder if it is worth trying to upstream... (given that it doesn't seem like this is going to be fixed quickly):

https://github.com/nathanchance/patches/blob/db2abfc9f51d/linux/build-hax/0003-DO-NOT-UPSTREAM-ARM-Don-t-select-HAVE_FUNCTION_TRACE.patch

We currently disable CONFIG_FTRACE for CI, the above change would give us a little extra build coverage.

nickdesaulniers · 2019-02-17T08:37:12Z

CONFIG_FTRACE selects a broken unwinder on arm, @vo4 is looking into this.

agners · 2019-02-17T09:28:53Z

@nickdesaulniers not sure what you mean, on ARM framepointer unwinder doesn't work with Clang, but the ARM EAPI unwinder should work fine. See also: https://lore.kernel.org/r/20180925212018.27132-1-stefan@agner.ch/

As state above, this is a LLVM issue. LLVM issue https://llvm.org/pr33845 needs to be resolved, then CONFIG_FTRACE should magically work. Maybe @smithp35 can have a look at it?

We could work around the LLVM issue since Linux uses a custom __gnu_mcount_nc implementation, I actually managed to hack up a version which works when compiling with LLVM/Clang. But not sure if we want such a hack in the kernel.

Another issue is that CONFIG_FUNCTION_GRAPH_TRACER only works with the framepointer unwinder (which does not work on Clang). I think technically a CONFIG_FUNCTION_GRAPH_TRACER which works with the ARM EABI unwinder should be doable, its just that nobody tackled it (yet). Russel would welcome such a change too: https://lore.kernel.org/r/20190113161420.GE2392@n2100.armlinux.org.uk/

agners · 2019-02-17T09:32:31Z

FWIW, this is the patch mentioned above: 0001-HACK-ARM-hack-ftrace-to-work-with-LLVM.patch.gz

smithp35 · 2019-02-18T14:47:06Z

I can add that pr to the list of things to look at although I've not got a lot of spare time right now so it may be some time before I can work on it.

vo4 · 2019-02-19T23:37:49Z

We could also resolve this problem by supporting CONFIG_FRAME_POINTER for Clang layout of the frame. In most cases it would only require adding clang-specific offsets from frame pointer to find stuff on the stack. The problem is that backtraces might not be as meaningful, because Clang implementation of AAPCS doesn't push pc register onto the stack.

vo4 · 2019-02-20T01:36:34Z

Building CONFIG_FRAME_POINTER for Clang frame layout will end up being essentially a revert of https://lore.kernel.org/r/20180826214022.4889-1-stefan@agner.ch/, since we'd need a custom mcount function. So getting clang to support "-pg -meabi gnu" is probably the more "correct" approach here.

nickdesaulniers · 2019-04-25T17:19:33Z

@vo4 , @nathanchance pointed out https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=503621628b32782a07b2318e4112bd4372aa3401 in the latest meeting notes. How does this affect arm32?

nathanchance · 2019-04-25T17:27:18Z

Unfortunately, I was a little preemptive in suggesting that this issue would be avoided with that patch. I still need to disable CONFIG_HAVE_FUNCTION_TRACER to avoid these linking errors :/

agners · 2019-04-26T07:49:34Z

Yeah there is another if !CC_IS_CLANG missing, I mentioned it, but it seems just slightly too late, a couple of hours after the patch got merged:
https://lore.kernel.org/r/20190414194705.2e10802aca2df36c8f27f349@kernel.org/

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig clang version check removed due to significant size of backporting 469cb73/2fd5b09c201e. Android R will not have a version of Clang < clang-10] Change-Id: I186771b7a3553652b84ee66dac6b53f7932b7076 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>

The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Link: https://git.kernel.org/linus/6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Link: https://git.kernel.org/linus/b0fe66cf095016e0b238374c10ae366e1f087d11 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

commit 6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 upstream. The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> [nd: configs were renamed in f9b58e8c7d03, CONFIG_CC_IS_{GCC|CLANG} did not exist until a435389/469cb7376c06] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Bug: 145525910 Change-Id: I9f595cff06a48498027e7dc1b958c35fc5da46e2

The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Link: https://git.kernel.org/linus/6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Link: https://git.kernel.org/linus/b0fe66cf095016e0b238374c10ae366e1f087d11 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

commit 6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 upstream. The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> [nd: configs were renamed in f9b58e8c7d03] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Bug: 145525910 Change-Id: I73f7b8b4161424229c2747d83687e0f1a4338cd1

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig change differs due to missing f00790aaf2e2] Change-Id: I280bd7c0422c68284ed31e2134ccef8997832737 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

The referenced issue ClangBuiltLinux/linux#35 was fixed in 2019 when clang 10 gained support for this feature on arm. Signed-off-by: Joel Stanley <joel@jms.id.au>

commit 6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 upstream. The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> [nd: configs were renamed in f9b58e8c7d03] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Bug: 145525910 Change-Id: I73f7b8b4161424229c2747d83687e0f1a4338cd1 (cherry picked from commit 2559c0730db99ab7e5ee54cbfd3ac6c22e974cdc) (cherry picked from commit 2d95772)

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig change differs due to missing f00790aaf2e2] Change-Id: I280bd7c0422c68284ed31e2134ccef8997832737 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> (cherry picked from commit 79259a5ee6c32b73ce0c1fd49ed820744ee73c77) (cherry picked from commit 868b38b)

In the existing NVMeOF Passthru core command handling on failure of nvme_alloc_request() it errors out with rq value set to NULL. In the error handling path it calls blk_put_request() without checking if rq is set to NULL or not which produces following Oops:- [ 1457.346861] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 1457.347838] #PF: supervisor read access in kernel mode [ 1457.348464] #PF: error_code(0x0000) - not-present page [ 1457.349085] PGD 0 P4D 0 [ 1457.349402] Oops: 0000 [#1] SMP NOPTI [ 1457.349851] CPU: 18 PID: 10782 Comm: kworker/18:2 Tainted: G OE 5.8.0-rc4nvme-5.9+ #35 [ 1457.350951] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e3214 [ 1457.352347] Workqueue: events nvme_loop_execute_work [nvme_loop] [ 1457.353062] RIP: 0010:blk_mq_free_request+0xe/0x110 [ 1457.353651] Code: 3f ff ff ff 83 f8 01 75 0d 4c 89 e7 e8 1b db ff ff e9 2d ff ff ff 0f 0b eb ef 66 8 [ 1457.355975] RSP: 0018:ffffc900035b7de0 EFLAGS: 00010282 [ 1457.356636] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 [ 1457.357526] RDX: ffffffffa060bd05 RSI: 0000000000000000 RDI: 0000000000000000 [ 1457.358416] RBP: 0000000000000037 R08: 0000000000000000 R09: 0000000000000000 [ 1457.359317] R10: 0000000000000000 R11: 000000000000006d R12: 0000000000000000 [ 1457.360424] R13: ffff8887ffa68600 R14: 0000000000000000 R15: ffff8888150564c8 [ 1457.361322] FS: 0000000000000000(0000) GS:ffff888814600000(0000) knlGS:0000000000000000 [ 1457.362337] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1457.363058] CR2: 0000000000000000 CR3: 000000081c0ac000 CR4: 00000000003406e0 [ 1457.363973] Call Trace: [ 1457.364296] nvmet_passthru_execute_cmd+0x150/0x2c0 [nvmet] [ 1457.364990] process_one_work+0x24e/0x5a0 [ 1457.365493] ? __schedule+0x353/0x840 [ 1457.365957] worker_thread+0x3c/0x380 [ 1457.366426] ? process_one_work+0x5a0/0x5a0 [ 1457.366948] kthread+0x135/0x150 [ 1457.367362] ? kthread_create_on_node+0x60/0x60 [ 1457.367934] ret_from_fork+0x22/0x30 [ 1457.368388] Modules linked in: nvme_loop(OE) nvmet(OE) nvme_fabrics(OE) null_blk nvme(OE) nvme_corer [ 1457.368414] ata_piix crc32c_intel virtio_pci libata virtio_ring serio_raw t10_pi virtio floppy dm_] [ 1457.380849] CR2: 0000000000000000 [ 1457.381288] ---[ end trace c6cab61bfd1f68fd ]--- [ 1457.381861] RIP: 0010:blk_mq_free_request+0xe/0x110 [ 1457.382469] Code: 3f ff ff ff 83 f8 01 75 0d 4c 89 e7 e8 1b db ff ff e9 2d ff ff ff 0f 0b eb ef 66 8 [ 1457.384749] RSP: 0018:ffffc900035b7de0 EFLAGS: 00010282 [ 1457.385393] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 [ 1457.386264] RDX: ffffffffa060bd05 RSI: 0000000000000000 RDI: 0000000000000000 [ 1457.387142] RBP: 0000000000000037 R08: 0000000000000000 R09: 0000000000000000 [ 1457.388029] R10: 0000000000000000 R11: 000000000000006d R12: 0000000000000000 [ 1457.388914] R13: ffff8887ffa68600 R14: 0000000000000000 R15: ffff8888150564c8 [ 1457.389798] FS: 0000000000000000(0000) GS:ffff888814600000(0000) knlGS:0000000000000000 [ 1457.390796] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1457.391508] CR2: 0000000000000000 CR3: 000000081c0ac000 CR4: 00000000003406e0 [ 1457.392525] Kernel panic - not syncing: Fatal exception [ 1457.394138] Kernel Offset: disabled [ 1457.394677] ---[ end Kernel panic - not syncing: Fatal exception ]--- We fix this Oops by adding a new goto label out_put_req and reordering the blk_put_request call to avoid calling blk_put_request() with rq value is set to NULL. Here we also update the rest of the code accordingly. Fixes: 06b7164dfdc0 ("nvmet: add passthru code to process commands") Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>

Get and put the reference to the ctrl in the nvme_dev_open() and nvme_dev_release() before and after module get/put for ctrl in char device file operations. Introduce char_dev relase function, get/put the controller and module which allows us to fix the potential Oops which can be easily reproduced with a passthru ctrl (although the problem also exists with pure user access): Entering kdb (current=0xffff8887f8290000, pid 3128) on processor 30 Oops: (null) due to oops @ 0xffffffffa01019ad CPU: 30 PID: 3128 Comm: bash Tainted: G W OE 5.8.0-rc4nvme-5.9+ #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.4 RIP: 0010:nvme_free_ctrl+0x234/0x285 [nvme_core] Code: 57 10 a0 e8 73 bf 02 e1 ba 3d 11 00 00 48 c7 c6 98 33 10 a0 48 c7 c7 1d 57 10 a0 e8 5b bf 02 e1 8 RSP: 0018:ffffc90001d63de0 EFLAGS: 00010246 RAX: ffffffffa05c0440 RBX: ffff8888119e45a0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8888177e9550 RDI: ffff8888119e43b0 RBP: ffff8887d4768000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffc90001d63c90 R12: ffff8888119e43b0 R13: ffff8888119e5108 R14: dead000000000100 R15: ffff8888119e5108 FS: 00007f1ef27b0740(0000) GS:ffff888817600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffa05c0470 CR3: 00000007f6bee000 CR4: 00000000003406e0 Call Trace: device_release+0x27/0x80 kobject_put+0x98/0x170 nvmet_passthru_ctrl_disable+0x4a/0x70 [nvmet] nvmet_passthru_enable_store+0x4c/0x90 [nvmet] configfs_write_file+0xe6/0x150 vfs_write+0xba/0x1e0 ksys_write+0x5f/0xe0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f1ef1eb2840 Code: Bad RIP value. RSP: 002b:00007fffdbff0eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1ef1eb2840 RDX: 0000000000000002 RSI: 00007f1ef27d2000 RDI: 0000000000000001 RBP: 00007f1ef27d2000 R08: 000000000000000a R09: 00007f1ef27b0740 R10: 0000000000000001 R11: 0000000000000246 R12: 00007f1ef2186400 R13: 0000000000000002 R14: 0000000000000001 R15: 0000000000000000 With this patch fix we take the module ref count in nvme_dev_open() and release that ref count in newly introduced nvme_dev_release(). Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>

@offset

This fixes the below mem leak. [ 130.157600] ============================================================================= [ 130.159662] BUG f2fs_page_array_entry-252:16 (Tainted: G W O ): Objects remaining in f2fs_page_array_entry-252:16 on __kmem_cache_shutdown() [ 130.162742] ----------------------------------------------------------------------------- [ 130.162742] [ 130.164979] Disabling lock debugging due to kernel taint [ 130.166188] INFO: Slab 0x000000009f5a52d2 objects=22 used=4 fp=0x00000000ba72c3e9 flags=0xfffffc0010200 [ 130.168269] CPU: 7 PID: 3560 Comm: umount Tainted: G B W O 5.9.0-rc4+ #35 [ 130.170019] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 [ 130.171941] Call Trace: [ 130.172528] dump_stack+0x74/0x9a [ 130.173298] slab_err+0xb7/0xdc [ 130.174044] ? kernel_poison_pages+0xc0/0xc0 [ 130.175065] ? on_each_cpu_cond_mask+0x48/0x90 [ 130.176096] __kmem_cache_shutdown.cold+0x34/0x141 [ 130.177190] kmem_cache_destroy+0x59/0x100 [ 130.178223] f2fs_destroy_page_array_cache+0x15/0x20 [f2fs] [ 130.179527] f2fs_put_super+0x1bc/0x380 [f2fs] [ 130.180538] generic_shutdown_super+0x72/0x110 [ 130.181547] kill_block_super+0x27/0x50 [ 130.182438] kill_f2fs_super+0x76/0xe0 [f2fs] [ 130.183448] deactivate_locked_super+0x3b/0x80 [ 130.184456] deactivate_super+0x3e/0x50 [ 130.185363] cleanup_mnt+0x109/0x160 [ 130.186179] __cleanup_mnt+0x12/0x20 [ 130.187003] task_work_run+0x70/0xb0 [ 130.187841] exit_to_user_mode_prepare+0x18f/0x1b0 [ 130.188917] syscall_exit_to_user_mode+0x31/0x170 [ 130.189989] do_syscall_64+0x45/0x90 [ 130.190828] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 130.191986] RIP: 0033:0x7faf868ea2eb [ 130.192815] Code: 7b 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 90 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 75 7b 0c 00 f7 d8 64 89 01 [ 130.196872] RSP: 002b:00007fffb7edb478 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 130.198494] RAX: 0000000000000000 RBX: 00007faf86a18204 RCX: 00007faf868ea2eb [ 130.201021] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055971df71c50 [ 130.203415] RBP: 000055971df71a40 R08: 0000000000000000 R09: 00007fffb7eda1f0 [ 130.205772] R10: 00007faf86a04339 R11: 0000000000000246 R12: 000055971df71c50 [ 130.208150] R13: 0000000000000000 R14: 000055971df71b38 R15: 0000000000000000 [ 130.210515] INFO: Object 0x00000000a980843a @offset=744 [ 130.212476] INFO: Allocated in page_array_alloc+0x3d/0xe0 [f2fs] age=1572 cpu=0 pid=3297 [ 130.215030] __slab_alloc+0x20/0x40 [ 130.216566] kmem_cache_alloc+0x2a0/0x2e0 [ 130.218217] page_array_alloc+0x3d/0xe0 [f2fs] [ 130.219940] f2fs_init_compress_ctx+0x1f/0x40 [f2fs] [ 130.221736] f2fs_write_cache_pages+0x3db/0x860 [f2fs] [ 130.223591] f2fs_write_data_pages+0x2c9/0x300 [f2fs] [ 130.225414] do_writepages+0x43/0xd0 [ 130.226907] __filemap_fdatawrite_range+0xd5/0x110 [ 130.228632] filemap_write_and_wait_range+0x48/0xb0 [ 130.230336] __generic_file_write_iter+0x18a/0x1d0 [ 130.232035] f2fs_file_write_iter+0x226/0x550 [f2fs] [ 130.233737] new_sync_write+0x113/0x1a0 [ 130.235204] vfs_write+0x1a6/0x200 [ 130.236579] ksys_write+0x67/0xe0 [ 130.237898] __x64_sys_write+0x1a/0x20 [ 130.239309] do_syscall_64+0x38/0x90 Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig clang version check removed due to significant size of backporting 469cb7376c06/2fd5b09c201e. Android R will not have a version of Clang < clang-10] Change-Id: I186771b7a3553652b84ee66dac6b53f7932b7076 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

commit 6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 upstream. The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> [nd: configs were renamed in f9b58e8c7d03, CONFIG_CC_IS_{GCC|CLANG} did not exist until a4353898980c/469cb7376c06] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Bug: 145525910 Change-Id: I9f595cff06a48498027e7dc1b958c35fc5da46e2

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig clang version check removed due to significant size of backporting 469cb7376c06/2fd5b09c201e. Android R will not have a version of Clang < clang-10] Change-Id: I186771b7a3553652b84ee66dac6b53f7932b7076 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

commit 6dc5fd93b2f1ef75d5e50fced8cb193811f25f22 upstream. The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> [nd: configs were renamed in f9b58e8c7d03, CONFIG_CC_IS_{GCC|CLANG} did not exist until a4353898980c/469cb7376c06] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Bug: 145525910 Change-Id: I9f595cff06a48498027e7dc1b958c35fc5da46e2

…r newer commit b0fe66cf095016e0b238374c10ae366e1f087d11 upstream. Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build with clang: arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': softirq.c:(.text+0x504): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': softirq.c:(.text+0x58c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': softirq.c:(.text+0x6c8): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': softirq.c:(.text+0x75c): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': softirq.c:(.text+0x840): undefined reference to `mcount' arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more undefined references to `mcount' follow clang can emit a working mcount symbol, __gnu_mcount_nc, when '-meabi gnu' is passed to it. Until r369147 in LLVM, this was broken and caused the kernel not to boot with '-pg' because the calling convention was not correct. Always build with '-meabi gnu' when using clang but ensure that '-pg' (which is added with CONFIG_FUNCTION_TRACER and its prereq CONFIG_HAVE_FUNCTION_TRACER) cannot be added with it unless this is fixed (which means using clang 10.0.0 and newer). Link: ClangBuiltLinux/linux#35 Link: https://bugs.llvm.org/show_bug.cgi?id=33845 Link: llvm/llvm-project@16fa8b0 Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Bug: 145525910 [nd: Kconfig clang version check removed due to significant size of backporting 469cb7376c06/2fd5b09c201e. Android R will not have a version of Clang < clang-10] Change-Id: I186771b7a3553652b84ee66dac6b53f7932b7076 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

The stackframe setup when compiled with clang is different. Since the stack unwinder expects the gcc stackframe setup it fails to print backtraces. This patch adds support for the clang stackframe setup. Link: ClangBuiltLinux/linux#35 Cc: clang-built-linux@googlegroups.com Suggested-by: Tri Vo <trong@google.com> Signed-off-by: Nathan Huckleberry <nhuck@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

agners added [BUG] linux A bug that should be fixed in the mainline kernel. [ARCH] arm32 This bug impacts ARCH=arm labels Sep 10, 2018

nickdesaulniers added the [BUG] llvm A bug that should be fixed in upstream LLVM label Sep 25, 2018

nickdesaulniers mentioned this issue Dec 10, 2018

arm32 allyesconfig build fails to link #288

Closed

nathanchance mentioned this issue Dec 14, 2018

--pic-vineer for arm32 lld #286

Closed

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 14, 2018

Disable ftrace on arm32

37192eb

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 14, 2018

Disable ftrace on arm32

469d7f5

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 14, 2018

Disable ftrace on arm32

7d847a2

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 14, 2018

Disable ftrace on arm32

61fd3f3

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 28, 2018

Disable ftrace on arm32

252c7d1

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added a commit to shenki/continuous-integration that referenced this issue Dec 29, 2018

Disable ftrace on arm32

124ca02

This is required to link the ARM kernel. For details see ClangBuiltLinux/linux#35. Signed-off-by: Joel Stanley <joel@jms.id.au>

shenki added the [ARCH] powerpc This bug impacts ARCH=powerpc label Jan 2, 2019

shenki mentioned this issue Jan 2, 2019

PPC64 (big endian) ClangBuiltLinux/continuous-integration#90

Closed

vo4 self-assigned this Feb 19, 2019

stephenhines mentioned this issue Feb 21, 2020

Assertion `!isa<CallBrInst>(Preds[i]->getTerminator()) && "Cannot split an edge from a CallBrInst"' failed. #896

Closed

shenki mentioned this issue Aug 7, 2020

driver: Don't skip ftrace on arm32 ClangBuiltLinux/continuous-integration#299

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Building with function tracer fails #35

Building with function tracer fails #35

agners commented Sep 10, 2018

agners commented Sep 10, 2018 •

edited by nathanchance

m-gupta commented Sep 12, 2018 •

edited by nathanchance

agners commented Nov 19, 2018 •

edited by nathanchance

shenki commented Jan 2, 2019

nathanchance commented Feb 15, 2019

nickdesaulniers commented Feb 17, 2019

agners commented Feb 17, 2019 •

edited by nathanchance

agners commented Feb 17, 2019

smithp35 commented Feb 18, 2019

vo4 commented Feb 19, 2019

vo4 commented Feb 20, 2019 •

edited by nathanchance

nickdesaulniers commented Apr 25, 2019

nathanchance commented Apr 25, 2019

agners commented Apr 26, 2019 •

edited by nathanchance

Building with function tracer fails #35

Building with function tracer fails #35

Comments

agners commented Sep 10, 2018

agners commented Sep 10, 2018 • edited by nathanchance

m-gupta commented Sep 12, 2018 • edited by nathanchance

agners commented Nov 19, 2018 • edited by nathanchance

shenki commented Jan 2, 2019

nathanchance commented Feb 15, 2019

nickdesaulniers commented Feb 17, 2019

agners commented Feb 17, 2019 • edited by nathanchance

agners commented Feb 17, 2019

smithp35 commented Feb 18, 2019

vo4 commented Feb 19, 2019

vo4 commented Feb 20, 2019 • edited by nathanchance

nickdesaulniers commented Apr 25, 2019

nathanchance commented Apr 25, 2019

agners commented Apr 26, 2019 • edited by nathanchance

agners commented Sep 10, 2018 •

edited by nathanchance

m-gupta commented Sep 12, 2018 •

edited by nathanchance

agners commented Nov 19, 2018 •

edited by nathanchance

agners commented Feb 17, 2019 •

edited by nathanchance

vo4 commented Feb 20, 2019 •

edited by nathanchance

agners commented Apr 26, 2019 •

edited by nathanchance