kernel/git/stable/linux.git/arch/mips, branch linux-5.10.y

KVM: Introduce vcpu->wants_to_run

2026-08-23T12:16:24+00:00

[ Upstream commit a6816314af5749cd88944bfdceb270c627cdf348 ] Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit was not set. Replace all references to vcpu->run->immediate_exit with !vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a malicious userspace could invoked KVM_RUN with immediate_exit=true and then after KVM reads it to set wants_to_run=false, flip it to false. This would result in the vCPU running in KVM_RUN with wants_to_run=false. This wouldn't cause any real bugs today but is a dangerous landmine. Signed-off-by: David Matlack Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com Signed-off-by: Sean Christopherson Stable-dep-of: e800decd9c0a ("KVM: x86: Only reset TSC Deadline Timer in apic_timer_expired on KVM_RUN") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mips: sched: Fix CPUMASK_OFFSTACK memory corruption

2026-08-19T15:12:13+00:00

[ Upstream commit 98e37db4a34d3af3fb2f4648295c25b5e40b20e3 ] This patch addresses a critical memory management flaw. When CONFIG_CPUMASK_OFFSTACK is enabled, cpumask_var_t is a pointer. Consequently, sizeof(new_mask) evaluates to the pointer size, causing copy_from_user() to clobber the mask pointer. Furthermore, the old logic performed copy_from_user() before allocating the mask. Fix this by allocating new_mask first. To handle variable-sized user masks correctly, use cpumask_size() to truncate overly large user masks or pad undersized masks with zeros before copying the data directly into the allocated buffer. Fixes: 295cbf6d63165 ("[MIPS] Move FPU affinity code into separate file.") Cc: stable@vger.kernel.org Signed-off-by: Aaron Tomlin Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: DEC: Ensure 32-bit stack location for o32 prom_printf()

2026-07-24T13:49:11+00:00

commit 5ff79e8bdc75db51e30298a75939e2308e7658e0 upstream. In 64-bit configurations calling any firmware entry points from a kernel thread other than the initial one will result in a situation where the stack has been placed in the XKPHYS 64-bit memory segment. Consequently the stack pointer is no longer a 32-bit value and when the 32-bit firmware code called uses 32-bit ALU operations to manipulate the stack pointer, the calculated result is incorrect (in fact in the 64-bit MIPS ISA almost all 32-bit ALU operations will produce an unpredictable result when executed on 64-bit data) and control goes astray. This may happen when no final console driver has been enabled in the configuration and consequently the initial console continues being used late into bootstrap, or with an upcoming change that will switch the zs driver to use a platform device, which in turn will make the console handover happen only after other kernel threads have already been started, and the kernel will hang at: pid_max: default: 32768 minimum: 301 or somewhat later, but always before: cblist_init_generic: Setting adjustable number of callback queues. has been printed. It seems that only the prom_printf() entry point is affected. Of all the other entry points wired only rex_slot_address() and rex_gettcinfo() are called from a kernel thread other than the initial one, specifically kernel_init(), and they are leaf functions that do no business with the stack, having worked with no issue ever since 64-bit support was added for the platform back in 2002. To address this issue then, arrange for the stack to be switched in the o32 wrapper as required for prom_printf() only, by supplying call_o32() with a pointer to a chunk of initdata space, which is placed in the CKSEG0 32-bit compatibility segment, observing that prom_printf() is only called from console output handler and therefore with the console lock held, implying no need for this code to be reentrant. Other firmware entry points may be called with interrupts enabled and no lock held, and may therefore require that call_o32() be reentrant. They trigger no issue at this point and "if it ain't broke, don't fix it," so just leave them alone. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v2.6.12+ Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: ip22-gio: fix device reference leak in probe

2026-07-24T13:49:11+00:00

commit b82930a4c5dbc5c4df39c0f93d968c239f2c6885 upstream. The gio probe function needlessly takes a device reference which is never released and therefore prevents unbound gio devices from being freed. Fixes: e84de0c61905 ("MIPS: GIO bus support for SGI IP22/28") Cc: stable@vger.kernel.org # 3.3 Cc: Thomas Bogendoerfer Signed-off-by: Johan Hovold Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: ip22-gio: fix kfree() of static object

2026-07-24T13:49:11+00:00

commit c62cdd3e919bdf84c37ec46810f87cdb1736e822 upstream. The gio bus root device is a statically allocated object which must not be freed by kfree() on failure to register the device or bus. Fixes: 82242d28ff8b ("MIPS: IP22: Add missing put_device call") Cc: stable@vger.kernel.org # 3.17 Cc: Levente Kurusa Signed-off-by: Johan Hovold Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: ip22-gio: fix gio device memory leak

2026-07-24T13:49:11+00:00

commit 7de9a1b45f5a95b58145653c525c8fb80292d9ab upstream. The gio device release callback was never wired up so gio devices are not freed when the last reference is dropped. Fixes: e84de0c61905 ("MIPS: GIO bus support for SGI IP22/28") Cc: stable@vger.kernel.org # 3.3 Cc: Thomas Bogendoerfer Signed-off-by: Johan Hovold Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: mm: Fix out-of-bounds write in maar_res_walk()

2026-07-24T13:49:00+00:00

[ Upstream commit 1b001b16bc88f3f7817e228acfd91ee01bdcfcce ] maar_res_walk() uses wi->num_cfg as the index into the fixed-size wi->cfg array, but checks whether the array is full only after it has filled the selected entry. If walk_system_ram_range() reports more than 16 memory ranges, the overflow call writes one struct maar_config past the end of the array before WARN_ON() prevents num_cfg from advancing. Move the full-array check before taking the array slot and return non-zero when the scratch array is full, so walk_system_ram_range() terminates the walk instead of invoking the callback for further ranges. Fixes: a5718fe8f70f ("MIPS: mm: Drop boot_mem_map") Signed-off-by: Yadan Fan Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: DEC: Remove do_IRQ() call indirection

2026-07-24T13:48:57+00:00

[ Upstream commit 35554eadc1b127bb5294504a4ac8f3a5dd9e299d ] As from commit 8f99a1626535 ("MIPS: Tracing: Add IRQENTRY_EXIT section for MIPS") do_IRQ() is not a macro anymore and can be invoked directly from assembly code, as a tail call. Remove the dec_irq_dispatch() stub then and the indirection previously introduced with commit 187933f23679 ("[MIPS] do_IRQ cleanup"), improving performance by reducing the number of control flow changes and the overall instruction count, while fixing a compiler's complaint about a missing prototype for said stub: arch/mips/dec/setup.c:780:25: warning: no previous prototype for 'dec_irq_dispatch' [-Wmissing-prototypes] 780 | asmlinkage unsigned int dec_irq_dispatch(unsigned int irq) | ^~~~~~~~~~~~~~~~ (which gets promoted to a compilation error with CONFIG_WERROR). Fixes: 8f99a1626535 ("MIPS: Tracing: Add IRQENTRY_EXIT section for MIPS") Signed-off-by: Maciej W. Rozycki Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: Fix big-endian stack argument fetching in o32 wrapper

2026-07-24T13:48:57+00:00

[ Upstream commit 8e0780d30b1b51248e42895b7acc7a20f147b40b ] Fix an issue in call_o32() where the upper 32-bit half of incoming n64 stack arguments is fetched and used for outgoing o32 stack arguments on big-endian platforms. This code was adapted from arch/mips/dec/prom/call_o32.S which was meant for a little-endian platform only and therefore using 32-bit loads from 64-bit stack slot locations holding incoming stack arguments resulted in correct values being retrieved for data that is expected to be 32-bit. This works on little-endian platforms where the lower 32-bit half of the 64-bit value is located at every 64-bit stack slot location. However on big-endian platforms the lower 32-bit half is instead located at offset 4 from every 64-bit stack slot location. So to fix the issue the offset of 4 would have to be used on big-endian platforms only, or alternatively a 64-bit load from the 64-bit stack slot location can be used across the board, as the subsequent 32-bit store to the corresponding outgoing stack argument slot will correctly truncate the value and cause no unpredictable result. We already take advantage of this architectural feature for the incoming arguments held in $a6 and $a7 registers, since the o32 wrapper does not know how many incoming arguments there are and consequently propagates incoming data which may not be 32-bit. Since this code is generally supposed to be used with the stack located in cached memory there is no extra overhead expected for 64-bit loads as opposed to 32-bit ones, so pick this variant for code simplicity. Fixes: 231a35d37293 ("[MIPS] RM: Collected changes") Signed-off-by: Maciej W. Rozycki Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: DEC: Prevent initial console buffer from landing in XKPHYS

2026-07-04T11:38:40+00:00

commit 7fb13fd35110ebe95eb053faf79d018f51144d85 upstream. In 64-bit configurations calling the initial console output handler from a kernel thread other than the initial one will result in a situation where the stack has been placed in the XKPHYS 64-bit memory segment and consequently so has been the buffer allocated there that is used as the argument corresponding to the `%s' output conversion specifier for the firmware's printf() entry point. This 64-bit address will then be truncated by 32-bit firmware, resulting in an attempt to access the wrong memory location, which in turn will cause all kinds of unpredictable behaviour, such as a kernel crash: Console: colour dummy device 160x64 Calibrating delay loop... 49.36 BogoMIPS (lpj=192512) pid_max: default: 32768 minimum: 301 CPU 0 Unable to handle kernel paging request at virtual address 000000000203bd00, epc == ffffffffbfc08364, ra == ffffffffbfc08800 Oops[#1]: CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc2-00254-gfb649bda6f56-dirty #121 $ 0 : 0000000000000000 0000000000000001 0000000000000023 ffffffff80684ba0 $ 4 : 000000000203bd00 ffffffffbfc0f3b4 ffffffffffffffff 0000000000000073 $ 8 : 0a303d7469000000 0000000000000000 0000000000000073 ffffffffbfc0f473 $12 : 0000000000000002 0000000000000000 ffffffff80684c1c 0000000000000000 $16 : 0000000000000000 ffffffff80596dc9 0000000000000000 ffffffffbfc09240 $20 : ffffffff80684c40 ffffffffbfc0f400 000000000000002d 000000000000002b $24 : ffffffffffffffbf 000000000203bd00 $28 : ffffffff805f0000 ffffffff80684b58 0000000000000030 ffffffffbfc08800 Hi : 0000000000000000 Lo : 0000000000000aa8 epc : ffffffffbfc08364 0xffffffffbfc08364 ra : ffffffffbfc08800 0xffffffffbfc08800 Status: 140120e2 KX SX UX KERNEL EXL Cause : 00000008 (ExcCode 02) BadVA : 000000000203bd00 PrId : 00000430 (R4000SC) Modules linked in: Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000) Stack : 0000000000000000 0000000000000000 0000000000000000 0000004d0000004d 80684cc0806a2a40 80596dc80000004d 8061000000000000 bfc0850c80684c38 0000000000000000 000000000203bd00 0000000000000000 0000000000000000 0000000000000000 00000000bfc0f3b4 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000002500000000 0000000000000000 0000000000000000 802c1a7400000000 0203bd0080596dc8 0203bd4d69000000 6c61632000000018 5f746567646e6172 6c616320625f6d6f 5f736e5f6d6f7266 206361323778302b 303d74696e726320 806a0a38806b0000 806a0a38806b0000 00000000806b0000 80683c58806b0000 ... Call Trace: Code: a082ffff 03e00008 00601021 <80820000> 00001821 10400005 24840001 80820000 24630001 ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Fatal exception in interrupt KN04 V2.1k (PC: 0xa0026768, SP: 0x806848e8) >> In this case the pointer in $4 was truncated from 0x980000000203bd00 to 0x000000000203bd00. This may happen when no final console driver has been enabled in the configuration and consequently the initial console continues being used late into bootstrap or with an upcoming change that will switch the zs driver to use a platform device, which in turn will make the console handover happen only after other kernel threads have already been started. Fix the issue by making the buffer static and initdata, and therefore placed in the CKSEG0 32-bit compatibility segment, observing that the console output handler is called with the console lock held, implying no need for this code to be reentrant. Add an assertion to verify the buffer actually has been placed in a compatibility segment. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v2.6.12+ Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman