Commit 673a55cc49 replaced the null pointer dereference used in
crashing_child() with __builtin_trap to address the following LLVM warnings:
coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
All coredump tests expect crashing_child() to result in a SIGSEGV. However, the
behavior of __builtin_trap is architecture-dependent. On x86 it yields SIGILL,
on aarch64 SIGTRAP. Given that neither of those signals are SIGSEGV, both
coredump_socket_test and coredump_socket_protocol_test are currently failing:
get_pidfd_info: mask=0xd7, coredump_mask=0x5, coredump_signal=5
socket_coredump_signal_sigsegv: coredump_signal=5, expected SIGSEGV=11
Qualify the pointer with volatile instead of calling __builtin_trap to fix the
tests.
Signed-off-by: Emanuele Rocca <emanuele.rocca@arm.com>
Link: https://patch.msgid.link/ab2kI0PI_Vk6bU88@NH27D9T0LF
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Use __builtin_trap() to truly crash the program instead of dereferencing
null pointer which may be optimized by the compiler preventing the crash
from occurring
[] Testing:
The diff between before and after of running the kselftest test of the
module shows no regression on system with x86 architecture
[] Error log:
~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/coredump$ make LLVM=1 W=1
CC stackdump_test
coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
59 | i = *(int *)NULL;
| ^~~~~~~~~~~~
coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
1 warning generated.
CC coredump_socket_test
coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
59 | i = *(int *)NULL;
| ^~~~~~~~~~~~
coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
1 warning generated.
CC coredump_socket_protocol_test
coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
59 | i = *(int *)NULL;
| ^~~~~~~~~~~~
coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
1 warning generated.
Link: https://lore.kernel.org/r/20251215084737.7504-1-clintbgeorge@gmail.com
Signed-off-by: Clint George <clintbgeorge@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Pull non-MM updates from Andrew Morton:
- "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
fixes a build issue and does some cleanup in ib/sys_info.c
- "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
enhances the 64-bit math code on behalf of a PWM driver and beefs up
the test module for these library functions
- "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
makes BPF symbol names, sizes, and line numbers available to the GDB
debugger
- "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
adds a sysctl which can be used to cause additional info dumping when
the hung-task and lockup detectors fire
- "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
adds a general base64 encoder/decoder to lib/ and migrates several
users away from their private implementations
- "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
makes TCP a little faster
- "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
reworks the KEXEC Handover interfaces in preparation for Live Update
Orchestrator (LUO), and possibly for other future clients
- "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
increases the flexibility of KEXEC Handover. Also preparation for LUO
- "Live Update Orchestrator" (Pasha Tatashin)
is a major new feature targeted at cloud environments. Quoting the
cover letter:
This series introduces the Live Update Orchestrator, a kernel
subsystem designed to facilitate live kernel updates using a
kexec-based reboot. This capability is critical for cloud
environments, allowing hypervisors to be updated with minimal
downtime for running virtual machines. LUO achieves this by
preserving the state of selected resources, such as memory,
devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving
memfd file descriptors, which allows critical in-memory data, such
as guest RAM or any other large memory region, to be maintained in
RAM across the kexec reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
moves the kexec and kdump sysfs entries from /sys/kernel/ to
/sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day
- "kho: fixes for vmalloc restoration" (Mike Rapoport)
fixes a BUG which was being hit during KHO restoration of vmalloc()
regions
* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
calibrate: update header inclusion
Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
vmcoreinfo: track and log recoverable hardware errors
kho: fix restoring of contiguous ranges of order-0 pages
kho: kho_restore_vmalloc: fix initialization of pages array
MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
init: replace simple_strtoul with kstrtoul to improve lpj_setup
KHO: fix boot failure due to kmemleak access to non-PRESENT pages
Documentation/ABI: new kexec and kdump sysfs interface
Documentation/ABI: mark old kexec sysfs deprecated
kexec: move sysfs entries to /sys/kernel/kexec
test_kho: always print restore status
kho: free chunks using free_page() instead of kfree()
selftests/liveupdate: add kexec test for multiple and empty sessions
selftests/liveupdate: add simple kexec-based selftest for LUO
selftests/liveupdate: add userspace API selftests
docs: add documentation for memfd preservation via LUO
mm: memfd_luo: allow preserving memfd
liveupdate: luo_file: add private argument to store runtime state
mm: shmem: export some functions to internal.h
...
Resolve a conflict between
commit 6a68d28066 ("selftests/coredump: Fix "socket_detect_userspace_client" test failure")
and
commit 994dc26302 ("selftests/coredump: fix build")
The first commit adds a read() to wait for write() from another thread to
finish. But the second commit removes the write().
Now that the two commits are in the same tree, the read() now gets EOF and
the test fails.
Remove this read() so that the test passes.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/20250811074957.4079616-1-namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull coredump updates from Christian Brauner:
"This contains an extension to the coredump socket and a proper rework
of the coredump code.
- This extends the coredump socket to allow the coredump server to
tell the kernel how to process individual coredumps. This allows
for fine-grained coredump management. Userspace can decide to just
let the kernel write out the coredump, or generate the coredump
itself, or just reject it.
* COREDUMP_KERNEL
The kernel will write the coredump data to the socket.
* COREDUMP_USERSPACE
The kernel will not write coredump data but will indicate to the
parent that a coredump has been generated. This is used when
userspace generates its own coredumps.
* COREDUMP_REJECT
The kernel will skip generating a coredump for this task.
* COREDUMP_WAIT
The kernel will prevent the task from exiting until the coredump
server has shutdown the socket connection.
The flexible coredump socket can be enabled by using the "@@"
prefix instead of the single "@" prefix for the regular coredump
socket:
@@/run/systemd/coredump.socket
- Cleanup the coredump code properly while we have to touch it
anyway.
Split out each coredump mode in a separate helper so it's easy to
grasp what is going on and make the code easier to follow. The core
coredump function should now be very trivial to follow"
* tag 'vfs-6.17-rc1.coredump' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (31 commits)
cleanup: add a scoped version of CLASS()
coredump: add coredump_skip() helper
coredump: avoid pointless variable
coredump: order auto cleanup variables at the top
coredump: add coredump_cleanup()
coredump: auto cleanup prepare_creds()
cred: add auto cleanup method
coredump: directly return
coredump: auto cleanup argv
coredump: add coredump_write()
coredump: use a single helper for the socket
coredump: move pipe specific file check into coredump_pipe()
coredump: split pipe coredumping into coredump_pipe()
coredump: move core_pipe_count to global variable
coredump: prepare to simplify exit paths
coredump: split file coredumping into coredump_file()
coredump: rename do_coredump() to vfs_coredump()
selftests/coredump: make sure invalid paths are rejected
coredump: validate socket path in coredump_parse()
coredump: don't allow ".." in coredump socket path
...
The coredump.socket_detect_userspace_client test occasionally fails:
# RUN coredump.socket_detect_userspace_client ...
# stackdump_test.c:500:socket_detect_userspace_client:Expected 0 (0) != WIFEXITED(status) (0)
# socket_detect_userspace_client: Test terminated by assertion
# FAIL coredump.socket_detect_userspace_client
not ok 3 coredump.socket_detect_userspace_client
because there is no guarantee that client's write() happens before server's
close(). The client gets terminated SIGPIPE, and thus the test fails.
Add a read() to server to make sure server's close() doesn't happen before
client's write().
Fixes: 7b6724fe9a ("selftests/coredump: add tests for AF_UNIX coredumps")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/20250620110252.1640391-1-namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Emanuele RoccaandChristian Brauner
Clint GeorgeandShuah Khan
Linus Torvalds
Bala-Vignesh-ReddyandAndrew Morton
Nam CaoandChristian Brauner