commit c366a7b5ed7564e41345c380285bd3f6cb98971b upstream.
debug_get_user_string() duplicates the userspace buffer with
memdup_user_nul() and then unconditionally looks at buffer[user_len - 1]
to strip a trailing newline.
A zero-length write reaches this helper unchanged, so the newline trim
reads before the start of the allocated buffer.
Reject empty writes before accessing the last input byte.
Fixes: 66a464dbc8e0 ("[PATCH] s390: debug feature changes")
Cc: stable@vger.kernel.org
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/20260417073530.96002-1-pengpeng@iscas.ac.cn
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e14622a7584f9608927c59a7d6ae4a0999dc545e upstream. debug_input_flush_fn() always copies one byte from the userspace buffer with copy_from_user() regardless of the supplied write length. A zero-length write therefore reads one byte beyond the caller's buffer. If the stale byte happens to be '-' or a digit the debug log is silently flushed. With an unmapped buffer the call returns -EFAULT. Reject zero-length writes before copying from userspace. Cc: stable@vger.kernel.org # v5.10+ Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
With PREEMPT_RT as potential configuration option, spinlock_t is now
considered as a sleeping lock, and thus might cause issues when used in
an atomic context. But even with PREEMPT_RT as potential configuration
option, raw_spinlock_t remains as a true spinning lock/atomic context.
This creates potential issues with the s390 debug/tracing feature. The
functions to trace errors are called in various contexts, including
under lock of raw_spinlock_t, and thus the used spinlock_t in each debug
area is in violation of the locking semantics.
Here are two examples involving failing PCI Read accesses that are
traced while holding `pci_lock` in `drivers/pci/access.c`:
=============================
[ BUG: Invalid wait context ]
6.19.0-devel #18 Not tainted
-----------------------------
bash/3833 is trying to lock:
0000027790baee30 (&rc->lock){-.-.}-{3:3}, at: debug_event_common+0xfc/0x300
other info that might help us debug this:
context-{5:5}
5 locks held by bash/3833:
#0: 0000027efbb29450 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x7c/0xf0
#1: 00000277f0504a90 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x13e/0x260
#2: 00000277beed8c18 (kn->active#339){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x164/0x260
#3: 00000277e9859190 (&dev->mutex){....}-{4:4}, at: pci_dev_lock+0x2e/0x40
#4: 00000383068a7708 (pci_lock){....}-{2:2}, at: pci_bus_read_config_dword+0x4a/0xb0
stack backtrace:
CPU: 6 UID: 0 PID: 3833 Comm: bash Kdump: loaded Not tainted 6.19.0-devel #18 PREEMPTLAZY
Hardware name: IBM 9175 ME1 701 (LPAR)
Call Trace:
[<00000383048afec2>] dump_stack_lvl+0xa2/0xe8
[<00000383049ba166>] __lock_acquire+0x816/0x1660
[<00000383049bb1fa>] lock_acquire+0x24a/0x370
[<00000383059e3860>] _raw_spin_lock_irqsave+0x70/0xc0
[<00000383048bbb6c>] debug_event_common+0xfc/0x300
[<0000038304900b0a>] __zpci_load+0x17a/0x1f0
[<00000383048fad88>] pci_read+0x88/0xd0
[<00000383054cbce0>] pci_bus_read_config_dword+0x70/0xb0
[<00000383054d55e4>] pci_dev_wait+0x174/0x290
[<00000383054d5a3e>] __pci_reset_function_locked+0xfe/0x170
[<00000383054d9b30>] pci_reset_function+0xd0/0x100
[<00000383054ee21a>] reset_store+0x5a/0x80
[<0000038304e98758>] kernfs_fop_write_iter+0x1e8/0x260
[<0000038304d995da>] new_sync_write+0x13a/0x180
[<0000038304d9c5d0>] vfs_write+0x200/0x330
[<0000038304d9c88c>] ksys_write+0x7c/0xf0
[<00000383059cfa80>] __do_syscall+0x210/0x500
[<00000383059e4c06>] system_call+0x6e/0x90
INFO: lockdep is turned off.
=============================
[ BUG: Invalid wait context ]
6.19.0-devel #3 Not tainted
-----------------------------
bash/6861 is trying to lock:
0000009da05c7430 (&rc->lock){-.-.}-{3:3}, at: debug_event_common+0xfc/0x300
other info that might help us debug this:
context-{5:5}
5 locks held by bash/6861:
#0: 000000acff404450 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x7c/0xf0
#1: 000000acff41c490 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x13e/0x260
#2: 0000009da36937d8 (kn->active#75){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x164/0x260
#3: 0000009dd15250d0 (&zdev->state_lock){+.+.}-{4:4}, at: enable_slot+0x2e/0xc0
#4: 000001a19682f708 (pci_lock){....}-{2:2}, at: pci_bus_read_config_byte+0x42/0xa0
stack backtrace:
CPU: 16 UID: 0 PID: 6861 Comm: bash Kdump: loaded Not tainted 6.19.0-devel #3 PREEMPTLAZY
Hardware name: IBM 9175 ME1 701 (LPAR)
Call Trace:
[<000001a194837ec2>] dump_stack_lvl+0xa2/0xe8
[<000001a194942166>] __lock_acquire+0x816/0x1660
[<000001a1949431fa>] lock_acquire+0x24a/0x370
[<000001a19596b810>] _raw_spin_lock_irqsave+0x70/0xc0
[<000001a194843b6c>] debug_event_common+0xfc/0x300
[<000001a194888b0a>] __zpci_load+0x17a/0x1f0
[<000001a194882d88>] pci_read+0x88/0xd0
[<000001a195453b88>] pci_bus_read_config_byte+0x68/0xa0
[<000001a195457bc2>] pci_setup_device+0x62/0xad0
[<000001a195458e70>] pci_scan_single_device+0x90/0xe0
[<000001a19488a0f6>] zpci_bus_scan_device+0x46/0x80
[<000001a19547f958>] enable_slot+0x98/0xc0
[<000001a19547f134>] power_write_file+0xc4/0x110
[<000001a194e20758>] kernfs_fop_write_iter+0x1e8/0x260
[<000001a194d215da>] new_sync_write+0x13a/0x180
[<000001a194d245d0>] vfs_write+0x200/0x330
[<000001a194d2488c>] ksys_write+0x7c/0xf0
[<000001a195957a30>] __do_syscall+0x210/0x500
[<000001a19596cbb6>] system_call+0x6e/0x90
INFO: lockdep is turned off.
Since it is desired to keep it possible to create trace records in most
situations, including this particular case (failing PCI config space
accesses are relevant), convert the used spinlock_t in `struct
debug_info` to raw_spinlock_t.
The impact is small, as the debug area lock only protects bounded memory
access without external dependencies, apart from one function
debug_set_size() where kfree() is implicitly called with the lock held.
Move debug_info_free() out of this lock, to keep remove this external
dependency.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel message catalog" which never made it upstream. Remove the macro in order to get rid of a pointless indirection. Replace all users with the string it defines. In almost all cases this leads to a simple replacement like this: - #define KMSG_COMPONENT "appldata" - #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + #define pr_fmt(fmt) "appldata: " fmt Except for some special cases this is just mechanical/scripted work. Acked-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Replace kmalloc() followed by copy_from_user() with memdup_user_nul() to improve and simplify debug_get_user_string(). Remove the manual NUL-termination. No functional changes intended. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Link: https://lore.kernel.org/r/20250804093321.434674-1-tigran.mkrtchyan@desy.de Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
The third argument of strscpy() is optional and can be left away iff the destination is an array and the maximum size of the copy is the size of destination. Remove the third argument for those cases where this is possible. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.
Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.
Created this by running an spatch followed by a sed command:
Spatch:
virtual patch
@
depends on !(file in "net")
disable optional_qualifier
@
identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@
+ const
struct ctl_table table_name [] = { ... };
sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c
Reviewed-by: Song Liu <song@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> # for kernel/trace/
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> # SCSI
Reviewed-by: Darrick J. Wong <djwong@kernel.org> # xfs
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Acked-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>