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This selects the THREAD_INFO_IN_TASK option for UM and changes the way
that the current task is discovered. This is trivial though, as UML
already tracks the current task in cpu_tasks[] and this can be used to
retrieve it.
Also remove the signal handler code that copies the thread information
into the IRQ stack. It is obsolete now, which also means that the
mentioned race condition cannot happen anymore.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Hajime Tazaki <thehajime@gmail.com>
Link: https://patch.msgid.link/20241111102910.46512-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When module text memory will be allocated with ROX permissions, the memory
at the actual address where the module will live will contain invalid
instructions and there will be a writable copy that contains the actual
module code.
Update relocations and alternatives patching to deal with it.
[rppt@kernel.org: fix writable address in cfi_rewrite_endbr()]
Link: https://lkml.kernel.org/r/ZysRwR29Ji8CcbXc@kernel.org
Link: https://lkml.kernel.org/r/20241023162711.2579610-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Several architectures support text patching, but they name the header
files that declare patching functions differently.
Make all such headers consistently named text-patching.h and add an empty
header in asm-generic for architectures that do not support text patching.
Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, show_stack() always dumps the trace of the current task.
However, it should dump the trace of the specified task if one is
provided. Otherwise, things like running "echo t > sysrq-trigger"
won't work as expected.
Fixes: 970e51feaddb ("um: Add support for CONFIG_STACKTRACE")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241106103933.1132365-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The drvdata is not available in release. Let's just use container_of()
to get the vector_device instance. Otherwise, removing a vector device
will result in a crash:
RIP: 0033:vector_device_release+0xf/0x50
RSP: 00000000e187bc40 EFLAGS: 00010202
RAX: 0000000060028f61 RBX: 00000000600f1baf RCX: 00000000620074e0
RDX: 000000006220b9c0 RSI: 0000000060551c80 RDI: 0000000000000000
RBP: 00000000e187bc50 R08: 00000000603ad594 R09: 00000000e187bb70
R10: 000000000000135a R11: 00000000603ad422 R12: 00000000623ae028
R13: 000000006287a200 R14: 0000000062006d30 R15: 00000000623700b6
Kernel panic - not syncing: Segfault with no mm
CPU: 0 UID: 0 PID: 16 Comm: kworker/0:1 Not tainted 6.12.0-rc6-g59b723cd2adb #1
Workqueue: events mc_work_proc
Stack:
60028f61 623ae028 e187bc80 60276fcd
6220b9c0 603f5820 623ae028 00000000
e187bcb0 603a2bcd 623ae000 62370010
Call Trace:
[<60028f61>] ? vector_device_release+0x0/0x50
[<60276fcd>] device_release+0x70/0xba
[<603a2bcd>] kobject_put+0xba/0xe7
[<60277265>] put_device+0x19/0x1c
[<60281266>] platform_device_put+0x26/0x29
[<60281e5f>] platform_device_unregister+0x2c/0x2e
[<60029422>] vector_remove+0x52/0x58
[<60031316>] ? mconsole_reply+0x0/0x50
[<600310c8>] mconsole_remove+0x160/0x1cc
[<603b19f4>] ? strlen+0x0/0x15
[<60066611>] ? __dequeue_entity+0x1a9/0x206
[<600666a7>] ? set_next_entity+0x39/0x63
[<6006666e>] ? set_next_entity+0x0/0x63
[<60038fa6>] ? um_set_signals+0x0/0x43
[<6003070c>] mc_work_proc+0x77/0x91
[<60057664>] process_scheduled_works+0x1b3/0x2dd
[<60055f32>] ? assign_work+0x0/0x58
[<60057f0a>] worker_thread+0x1e9/0x293
[<6005406f>] ? set_pf_worker+0x0/0x64
[<6005d65d>] ? arch_local_irq_save+0x0/0x2d
[<6005d748>] ? kthread_exit+0x0/0x3a
[<60057d21>] ? worker_thread+0x0/0x293
[<6005dbf1>] kthread+0x126/0x12b
[<600219c5>] new_thread_handler+0x85/0xb6
Cc: stable@vger.kernel.org
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://patch.msgid.link/20241104163203.435515-5-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The drvdata is not available in release. Let's just use container_of()
to get the uml_net instance. Otherwise, removing a network device will
result in a crash:
RIP: 0033:net_device_release+0x10/0x6f
RSP: 00000000e20c7c40 EFLAGS: 00010206
RAX: 000000006002e4e7 RBX: 00000000600f1baf RCX: 00000000624074e0
RDX: 0000000062778000 RSI: 0000000060551c80 RDI: 00000000627af028
RBP: 00000000e20c7c50 R08: 00000000603ad594 R09: 00000000e20c7b70
R10: 000000000000135a R11: 00000000603ad422 R12: 0000000000000000
R13: 0000000062c7af00 R14: 0000000062406d60 R15: 00000000627700b6
Kernel panic - not syncing: Segfault with no mm
CPU: 0 UID: 0 PID: 29 Comm: kworker/0:2 Not tainted 6.12.0-rc6-g59b723cd2adb #1
Workqueue: events mc_work_proc
Stack:
627af028 62c7af00 e20c7c80 60276fcd
62778000 603f5820 627af028 00000000
e20c7cb0 603a2bcd 627af000 62770010
Call Trace:
[<60276fcd>] device_release+0x70/0xba
[<603a2bcd>] kobject_put+0xba/0xe7
[<60277265>] put_device+0x19/0x1c
[<60281266>] platform_device_put+0x26/0x29
[<60281e5f>] platform_device_unregister+0x2c/0x2e
[<6002ec9c>] net_remove+0x63/0x69
[<60031316>] ? mconsole_reply+0x0/0x50
[<600310c8>] mconsole_remove+0x160/0x1cc
[<60087d40>] ? __remove_hrtimer+0x38/0x74
[<60087ff8>] ? hrtimer_try_to_cancel+0x8c/0x98
[<6006b3cf>] ? dl_server_stop+0x3f/0x48
[<6006b390>] ? dl_server_stop+0x0/0x48
[<600672e8>] ? dequeue_entities+0x327/0x390
[<60038fa6>] ? um_set_signals+0x0/0x43
[<6003070c>] mc_work_proc+0x77/0x91
[<60057664>] process_scheduled_works+0x1b3/0x2dd
[<60055f32>] ? assign_work+0x0/0x58
[<60057f0a>] worker_thread+0x1e9/0x293
[<6005406f>] ? set_pf_worker+0x0/0x64
[<6005d65d>] ? arch_local_irq_save+0x0/0x2d
[<6005d748>] ? kthread_exit+0x0/0x3a
[<60057d21>] ? worker_thread+0x0/0x293
[<6005dbf1>] kthread+0x126/0x12b
[<600219c5>] new_thread_handler+0x85/0xb6
Cc: stable@vger.kernel.org
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://patch.msgid.link/20241104163203.435515-4-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The drvdata is not available in release. Let's just use container_of()
to get the ubd instance. Otherwise, removing a ubd device will result
in a crash:
RIP: 0033:blk_mq_free_tag_set+0x1f/0xba
RSP: 00000000e2083bf0 EFLAGS: 00010246
RAX: 000000006021463a RBX: 0000000000000348 RCX: 0000000062604d00
RDX: 0000000004208060 RSI: 00000000605241a0 RDI: 0000000000000348
RBP: 00000000e2083c10 R08: 0000000062414010 R09: 00000000601603f7
R10: 000000000000133a R11: 000000006038c4bd R12: 0000000000000000
R13: 0000000060213a5c R14: 0000000062405d20 R15: 00000000604f7aa0
Kernel panic - not syncing: Segfault with no mm
CPU: 0 PID: 17 Comm: kworker/0:1 Not tainted 6.8.0-rc3-00107-gba3f67c11638 #1
Workqueue: events mc_work_proc
Stack:
00000000 604f7ef0 62c5d000 62405d20
e2083c30 6002c776 6002c755 600e47ff
e2083c60 6025ffe3 04208060 603d36e0
Call Trace:
[<6002c776>] ubd_device_release+0x21/0x55
[<6002c755>] ? ubd_device_release+0x0/0x55
[<600e47ff>] ? kfree+0x0/0x100
[<6025ffe3>] device_release+0x70/0xba
[<60381d6a>] kobject_put+0xb5/0xe2
[<6026027b>] put_device+0x19/0x1c
[<6026a036>] platform_device_put+0x26/0x29
[<6026ac5a>] platform_device_unregister+0x2c/0x2e
[<6002c52e>] ubd_remove+0xb8/0xd6
[<6002bb74>] ? mconsole_reply+0x0/0x50
[<6002b926>] mconsole_remove+0x160/0x1cc
[<6002bbbc>] ? mconsole_reply+0x48/0x50
[<6003379c>] ? um_set_signals+0x3b/0x43
[<60061c55>] ? update_min_vruntime+0x14/0x70
[<6006251f>] ? dequeue_task_fair+0x164/0x235
[<600620aa>] ? update_cfs_group+0x0/0x40
[<603a0e77>] ? __schedule+0x0/0x3ed
[<60033761>] ? um_set_signals+0x0/0x43
[<6002af6a>] mc_work_proc+0x77/0x91
[<600520b4>] process_scheduled_works+0x1af/0x2c3
[<6004ede3>] ? assign_work+0x0/0x58
[<600527a1>] worker_thread+0x2f7/0x37a
[<6004ee3b>] ? set_pf_worker+0x0/0x64
[<6005765d>] ? arch_local_irq_save+0x0/0x2d
[<60058e07>] ? kthread_exit+0x0/0x3a
[<600524aa>] ? worker_thread+0x0/0x37a
[<60058f9f>] kthread+0x130/0x135
[<6002068e>] new_thread_handler+0x85/0xb6
Cc: stable@vger.kernel.org
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://patch.msgid.link/20241104163203.435515-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Currently, the initialization of the disk pointer in the ubd structure
is missing. It should be initialized with the allocated gendisk pointer
in ubd_add().
Fixes: 32621ad7a7ea ("ubd: remove the ubd_gendisk array")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://patch.msgid.link/20241104163203.435515-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When the VHOST_USER_PROTOCOL_F_MQ protocol feature flag is set, we can
query the maximum number of virtual queues. Do so when supported and
extend the check to verify that we are not trying to allocate more
queues.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103212854.1436046-5-benjamin@sipsolutions.net
[add a message to the WARN_ON]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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If the device does not support slave requests, then the IRQ will not yet
be allocated. So initialize the IRQ to UM_IRQ_ALLOC so that it will be
allocated if none has been assigned yet and store it slightly later when
we know that it will not be immediately unregistered again.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103212854.1436046-4-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The rust based userspace vhost devices are very strict and will not
accept the message if it is longer than required. So, only include the
data for the first memory region.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103212854.1436046-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The show_stack function had some code to detect double faults. However,
the logic is wrong and it would e.g. trigger if a WARNING happened
inside an IRQ.
Remove it without trying to add a new logic. The current behaviour,
which will just fault repeatedly until the IRQ stack is used up and the
host kills UML, seems to be good enough.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-5-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Just remove the first entry as there is a second later on.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-4-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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There is no need to sync the stub code to "disk" for the other process
to see the correct memory. Drop the fsync there and remove the helper
function.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-3-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Since commit a95b37e20db9 ("kbuild: get <linux/compiler_types.h> out of
<linux/kconfig.h>") we can safely include these files in userspace code.
Doing so simplifies matters as options do not need to be exported via
asm-offsets.h anymore.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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There is no point in either dumping the KASAN shadow memory or doing
copy-on-write after a fork on these memory regions.
This considerably speeds up coredump generation.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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free_pages() performs a parameter null check inside
therefore remove double zero check here.
Signed-off-by: Shaojie Dong <quic_shaojied@quicinc.com>
Link: https://patch.msgid.link/20241025-upstream_branch-v5-1-b8998beb2c64@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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__pa() is only intended to be used for linear map addresses and using
it for initial_boot_params which is in fixmap for arm64 will give an
incorrect value. Hence save the physical address when it is known at
boot time when calling early_init_dt_scan for arm64 and use it at kexec
time instead of converting the virtual address using __pa().
Note that arm64 doesn't need the FDT region reserved in the DT as the
kernel explicitly reserves the passed in FDT. Therefore, only a debug
warning is fixed with this change.
Reported-by: Breno Leitao <leitao@debian.org>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Fixes: ac10be5cdbfa ("arm64: Use common of_kexec_alloc_and_setup_fdt()")
Link: https://lore.kernel.org/r/20241023171426.452688-1-usamaarif642@gmail.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
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page_to_phys is duplicated by all architectures, and from some strange
reason placed in <asm/io.h> where it doesn't fit at all.
phys_to_page is only provided by a few architectures despite having a lot
of open coded users.
Provide generic versions in <asm-generic/memory_model.h> to make these
helpers more easily usable.
Note with this patch powerpc loses the CONFIG_DEBUG_VIRTUAL pfn_valid
check. It will be added back in a generic version later.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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CONFIG_GCOV is special and only in UML since it builds the
kernel with a "userspace" option. This is fine, but the stub
is even more special and not really a full userspace process,
so it then fails to link as reported.
Remove the GCOV options from the stub build.
For good measure, also remove the GPROF options, even though
they don't seem to cause build failures now.
To be able to do this, export the specific options (GCOV_OPT
and GPROF_OPT) but rename them so there's less chance of any
conflicts.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410242238.SXhs2kQ4-lkp@intel.com/
Fixes: 32e8eaf263d9 ("um: use execveat to create userspace MMs")
Link: https://patch.msgid.link/20241025102700.9fbb9c34473f.I7f1537fe075638f8da64beb52ef6c9e5adc51bc3@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Since we have a helper now, let's switch to using it. It will make
the code slightly more consistent.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-5-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The write_sigio thread is not really a traditional thread. Set
the parent-death signal for it to ensure that it will be killed
if the UML kernel dies unexpectedly without proper cleanup.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-4-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The ubd io thread is not really a traditional thread. Set the
parent-death signal for it to ensure that it will be killed if
the UML kernel dies unexpectedly without proper cleanup.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This helper can be used to set the parent-death signal of the calling
process to SIGKILL to ensure that the process will be killed if the
UML kernel dies unexpectedly without proper cleanup. This helper will
be used in the follow-up patches.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Evidently, PATH_MAX isn't always defined, at least not via <limits.h>.
Simply remove the use and replace it by a constant 4k. As stat::st_size
is zero for /proc/self/exe we can't even size it automatically, and it
seems unlikely someone's going to try to run UML with such a path.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410240553.gYNIXN8i-lkp@intel.com/
Fixes: 031acdcfb566 ("um: restore process name")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The PTRACE_GETREGSET API has now existed since Linux 2.6.33. The XSAVE
CPU feature should also be sufficiently common to be able to rely on it.
With this, define our internal FP state to be the hosts XSAVE data. Add
discovery for the hosts XSAVE size and place the FP registers at the end
of task_struct so that we can adjust the size at runtime.
Next we can implement the regset API on top and update the signal
handling as well as ptrace APIs to use them. Also switch coredump
creation to use the regset API and finally set HAVE_ARCH_TRACEHOOK.
This considerably improves the signal frames. Previously they might not
have contained all the registers (i386) and also did not have the
sizes and magic values set to the correct values to permit userspace to
decode the frame.
As a side effect, this will permit UML to run on hosts with newer CPU
extensions (such as AMX) that need even more register state.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241023094120.4083426-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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In time-travel mode userspace can do a lot of work without any time
passing. Unfortunately, this can result in OOM situations as the RCU
core code will never be run.
Work around this by keeping track of userspace processes that do not
yield for a lot of operations. When this happens, insert a jiffie into
the sched_clock clock to account time against the process and cause the
bookkeeping to run.
As sched_clock is used for tracing, it is useful to keep it in sync
between the different VMs. As such, try to remove added ticks again when
the actual clock ticks.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241010142537.1134685-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The _PAGE_NEWPAGE bit does not really indicate that this is a new page,
but rather whether this entry needs to be synced or not. Renaming it
to _PAGE_NEEDSYNC will make it more clear how everything ties together.
Suggested-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011102354.1682626-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When a PTE is updated in the page table, the _PAGE_NEWPAGE bit will
always be set. And the corresponding page will always be mapped or
unmapped depending on whether the PTE is present or not. The check
on the _PAGE_NEWPROT bit is not really reachable. Abandoning it will
allow us to simplify the code and remove the unreachable code.
Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011102354.1682626-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific. It specifies the name of the file
containing the initrd image, which is unknown to kernel.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-10-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should
not be propagated to kernel, otherwise it will trigger a warning and
be passed to user space as an environment option.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-9-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should
not be propagated to kernel, otherwise it will trigger a warning and
be passed to user space as an environment option.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-8-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should not
be propagated to kernel, otherwise it could be passed to user space as
a command line option by kernel with a warning like:
Unknown kernel command line parameters "noreboot", will be passed to user space.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-6-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should not
be propagated to kernel, otherwise it will be passed to user space as
an environment option by kernel with a warning like:
Unknown kernel command line parameters "dtb=/foo", will be passed to user space.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-5-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should not
be propagated to kernel, otherwise it will be passed to user space as
an environment option by kernel with a warning like:
Unknown kernel command line parameters "uml_dir=/foo", will be passed to user space.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-4-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This parameter is UML specific and is unknown to kernel. It should not
be propagated to kernel, otherwise it will be passed to user space as
an environment option by kernel with a warning like:
Unknown kernel command line parameters "mem=2G", will be passed to user space.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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It does nothing but emit a warning when 'debug' is provided in the
kernel command line. It can be a bit annoying, as 'debug' is also a
valid kernel parameter to enable kernel debugging.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241011040441.1586345-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This was perhaps intended to do _nofault copies, but the
real reason is lost to history. Remove this, it's not
needed, and using longjmp() out of the middle of the
signal handler with all the state it has modified is
not going to be a good idea anyway.
Link: https://patch.msgid.link/20241010224513.901c4d390b3e.Ia74742668b44603c1ca23dd36f90e964e6e7ee55@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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After the execve() to disable ASLR, comm is now "exe",
which is a bit confusing. Use readlink() to get this
to the right name again.
Disable stack frame size warnings on main.o since it's
part of the initial userspace and can use larger stack.
Fixes: 68b9883cc16e ("um: Discover host_task_size from envp")
Link: https://patch.msgid.link/20241010161411.c576e2aeb3e5.I244d4f34b8a8555ee5bec0e1cf5027bce4cc491b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Since __attribute__((naked)) cannot be used with functions
containing C statements, just generate the few instructions
it needs in assembly directly.
While at it, fix the stack usage ("1 + 2*x - 1" is odd) and
document what it must do, and why it must adjust the stack.
Fixes: 8508a5e0e9db ("um: Fix misaligned stack in stub_exe")
Link: https://lore.kernel.org/linux-um/CABVgOSntH-uoOFMP5HwMXjx_f1osMnVdhgKRKm4uz6DFm2Lb8Q@mail.gmail.com/
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Deprecation period of reiserfs ends with the end of this year so it is
time to remove it from the kernel.
Acked-by: Darrick J. Wong <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
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The stub_exe could segfault when built with some compilers (e.g. gcc
13.2.0), as SSE instructions which relied on stack alignment could be
generated, but the stack was misaligned.
This seems to be due to the __start entry point being run with a 16-byte
aligned stack, but the x86_64 SYSV ABI wanting the stack to be so
aligned _before_ a function call (so it is misaligned when the function
is entered due to the return address being pushed). The function
prologue then realigns it. Because the entry point is never _called_,
and hence there is no return address, the prologue is therefore actually
misaligning it, and causing the generated movaps instructions to
SIGSEGV. This results in the following error:
start_userspace : expected SIGSTOP, got status = 139
Don't generate this prologue for __start by using
__attribute__((naked)), which resolves the issue.
Fixes: 32e8eaf263d9 ("um: use execveat to create userspace MMs")
Signed-off-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/linux-um/CABVgOS=boUoG6=LHFFhxEd8H8jDP1zOaPKFEjH+iy2n2Q5S2aQ@mail.gmail.com/
Link: https://patch.msgid.link/20241017231007.1500497-2-davidgow@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When automatic variable initialization is enabled via
CONFIG_INIT_STACK_ALL_{PATTERN,ZERO}, clang will insert a call to
memset() to initialize an object created with __builtin_alloca(). This
ultimately breaks the build when linking stub_exe because it is a
standalone executable that does not include or link against memset().
ld: arch/um/kernel/skas/stub_exe.o: in function `_start':
arch/um/kernel/skas/stub_exe.c:83:(.ltext+0x15): undefined reference to `memset'
Disable automatic variable initialization for stub_exe.c by passing the
default value of 'uninitialized' to '-ftrivial-auto-var-init', which
avoids generating the call to memset(). This code is small and runs
quickly as it is just designed to set up an environment, so stack
variable initialization is unnecessary overhead for little gain.
Fixes: 32e8eaf263d9 ("um: use execveat to create userspace MMs")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20241016-uml-fix-stub_exe-clang-v1-2-3d6381dc5a78@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When building stub_exe with clang, there is an error because '-n' is not
a recognized flag by the clang driver (which is being used to invoke the
linker):
clang: error: unknown argument: '-n'
'-n' should be passed along to the linker, as it is the short flag for
'--nmagic', so prefix it with '-Wl,'.
Fixes: 32e8eaf263d9 ("um: use execveat to create userspace MMs")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20241016-uml-fix-stub_exe-clang-v1-1-3d6381dc5a78@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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The VDSO implementation includes headers from outside of the
vdso/ namespace.
Introduce vdso/page.h to make sure that the generic library
uses only the allowed namespace.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Link: https://lore.kernel.org/all/20241014151340.1639555-3-vincenzo.frascino@arm.com
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The larger memory space is useful to support more applications inside
UML. One example for this is ASAN instrumentation of userspace
applications which requires addresses that would otherwise not be
available.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-11-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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With the change to use execve() we can now safely clear the memory up to
STUB_START as rseq will not be trying to use memory in that region. Also,
on 64 bit the previous changes should mean that there is no usable
memory range above the stub.
Make the change and remove the comment as it is not needed anymore.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-10-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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When loading the UML binary, the host kernel will place the stack at the
highest possible address. It will then map the program name and
environment variables onto the start of the stack.
As such, an easy way to figure out the host_task_size is to use the
highest pointer to an environment variable as a reference.
Ensure that this works by disabling address layout randomization and
re-executing UML in case it was enabled.
This increases the available TASK_SIZE for 64 bit UML considerably.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-9-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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We may have a TASK_SIZE from the host that is bigger than UML is able to
address with a three-level pagetable on 64-bit. Guard against that by
clipping the maximum TASK_SIZE to the maximum addressable area.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-8-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Instead of using the current stack pointer, we can also use the current
instruction to calculate where the stub data is. With this the stub data
only needs to be aligned to a full page boundary.
Changing this has the advantage that we do not have a hole in the memory
space above the stub data (which would need to be explicitly cleared).
Another motivation to do this is that with the planned addition of a
SECCOMP based userspace the stack pointer may not be fully trustworthy.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-7-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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