commit d187a86de793f84766ea40b9ade7ac60aabbb4fe upstream. This function was a masterclass in bad naming, for various historical reasons. It claimed to be a non-cached user copy. It is literally _neither_ of those things. It's a specialty memory copy routine that uses non-temporal stores for the destination (but not the source), and that does exception handling for both source and destination accesses. Also note that while it works for unaligned targets, any unaligned parts (whether at beginning or end) will not use non-temporal stores, since only words and quadwords can be non-temporal on x86. The exception handling means that it _can_ be used for user space accesses, but not on its own - it needs all the normal "start user space access" logic around it. But typically the user space access would be the source, not the non-temporal destination. That was the original intention of this, where the destination was some fragile persistent memory target that needed non-temporal stores in order to catch machine check exceptions synchronously and deal with them gracefully. Thus that non-descriptive name: one use case was to copy from user space into a non-cached kernel buffer. However, the existing users are a mix of that intended use-case, and a couple of random drivers that just did this as a performance tweak. Some of those random drivers then actively misused the user copying version (with STAC/CLAC and all) to do kernel copies without ever even caring about the exception handling, _just_ for the non-temporal destination. Rename it as a first small step to actually make it halfway sane, and change the prototype to be more normal: it doesn't take a user pointer unless the caller has done the proper conversion, and the argument size is the full size_t (it still won't actually copy more than 4GB in one go, but there's also no reason to silently truncate the size argument in the caller). Finally, use this now sanely named function in the NTB code, which mis-used a user copy version (with STAC/CLAC and all) of this interface despite it not actually being a user copy at all. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With Clang, there can be a conditional forward jump between the load of the jump table address and the indirect branch. Fixes the following warning: vmlinux.o: warning: objtool: ___bpf_prog_run+0x1c5: sibling call from callable instruction with modified stack frame Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com Link: https://patch.msgid.link/7d8600caed08901b6679767488acd639f6df9688.1773071992.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The elf_create_file() function fails with EINVAL when the build directory path is long enough to truncate the "XXXXXX" suffix in the 256-byte tmp_name buffer. Simplify the code to remove the unnecessary dirname()/basename() split and concatenation. Instead, allocate the exact number of bytes needed for the path. Acked-by: Song Liu <song@kernel.org> Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Link: https://patch.msgid.link/20260310203751.1479229-3-joe.lawrence@redhat.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Commit 356e4b2f5b80 ("objtool: Fix data alignment in elf_add_data()")
corrected the alignment of data within a section (honoring the section's
sh_addralign). Apply the same alignment when klp-diff mode clones a
symbol, adjusting the new symbol's offset for the output section's
sh_addralign.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-2-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Pull objtool fixes from Ingo Molnar: - Fix cross-build bug by using HOSTCFLAGS for HAVE_XXHASH test - Fix klp bug by fixing detection of corrupt static branch/call entries - Handle unsupported pr_debug() usage more gracefully - Fix hypothetical klp bug by avoiding NULL pointer dereference when printing code symbol name - Fix data alignment bug in elf_add_data() causing mangled strings - Fix confusing ERROR_INSN() error message - Handle unexpected Clang RSP musical chairs causing false positive warnings - Fix another objtool stack overflow in validate_branch() * tag 'objtool-urgent-2026-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Fix another stack overflow in validate_branch() objtool: Handle Clang RSP musical chairs objtool: Fix ERROR_INSN() error message objtool: Fix data alignment in elf_add_data() objtool: Use HOSTCFLAGS for HAVE_XXHASH test objtool/klp: Avoid NULL pointer dereference when printing code symbol name objtool/klp: Disable unsupported pr_debug() usage objtool/klp: Fix detection of corrupt static branch/call entries
The insn state is getting saved on the stack twice for each recursive
iteration. No need for that, once is enough.
Fixes the following reported stack overflow:
drivers/scsi/qla2xxx/qla_dbg.o: error: SIGSEGV: objtool stack overflow!
Segmentation fault
Fixes: 70589843b36f ("objtool: Add option to trace function validation")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com
Link: https://patch.msgid.link/8b97f62d083457f3b0a29a424275f7957dd3372f.1772821683.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
For no apparent reason (possibly related to CONFIG_KMSAN), Clang can randomly pass the value of RSP to other registers and then back again to RSP. Handle that accordingly. Fixes the following warnings: drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1 Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Confusingly, ERROR_INSN() shows "warning:" instead of "error:". Fix that. Link: https://patch.msgid.link/c4fe793bb3d23fac2c636b2511059af1158410e2.1772681234.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Any data added to a section needs to be aligned in accordance with the
section's sh_addralign value. Particularly strings added to a .str1.8
section. Otherwise you may get some funky strings.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Link: https://patch.msgid.link/d962fc0ca24fa0825cca8dad71932dccdd9312a9.1772681234.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Previously, HAVE_XXHASH is tested by invoking HOSTCC without HOSTCFLAGS.
Consider the following scenario:
- The host machine has libxxhash installed
- We build the kernel with HOSTCFLAGS containing a --sysroot that does
not have xxhash.h (for hermetic builds)
In this case, HAVE_XXHASH is set to y, but when it builds objtool with
HOSTCFLAGS, because the --sysroot does not contain xxhash.h, the
following error is raised:
<...>/common/tools/objtool/include/objtool/checksum_types.h:12:10: fatal error: 'xxhash.h' file not found
12 | #include <xxhash.h>
| ^~~~~~~~~~
To resolve the error, we test HAVE_XXHASH by invoking HOSTCC with
HOSTCFLAGS.
Signed-off-by: HONG Yifan <elsk@google.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Link: https://patch.msgid.link/20260303010340.306164-1-elsk@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>