Nam Cao fb1cf08783 riscv: rewrite __kernel_map_pages() to fix sleeping in invalid context ... __kernel_map_pages() is a debug function which clears the valid bit in page table entry for deallocated pages to detect illegal memory accesses to freed pages. This function set/clear the valid bit using __set_memory(). __set_memory() acquires init_mm's semaphore, and this operation may sleep. This is problematic, because __kernel_map_pages() can be called in atomic context, and thus is illegal to sleep. An example warning that this causes: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd preempt_count: 2, expected: 0 CPU: 0 PID: 2 Comm: kthreadd Not tainted 6.9.0-g1d4c6d784ef6 #37 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff800060dc>] dump_backtrace+0x1c/0x24 [<ffffffff8091ef6e>] show_stack+0x2c/0x38 [<ffffffff8092baf8>] dump_stack_lvl+0x5a/0x72 [<ffffffff8092bb24>] dump_stack+0x14/0x1c [<ffffffff8003b7ac>] __might_resched+0x104/0x10e [<ffffffff8003b7f4>] __might_sleep+0x3e/0x62 [<ffffffff8093276a>] down_write+0x20/0x72 [<ffffffff8000cf00>] __set_memory+0x82/0x2fa [<ffffffff8000d324>] __kernel_map_pages+0x5a/0xd4 [<ffffffff80196cca>] __alloc_pages_bulk+0x3b2/0x43a [<ffffffff8018ee82>] __vmalloc_node_range+0x196/0x6ba [<ffffffff80011904>] copy_process+0x72c/0x17ec [<ffffffff80012ab4>] kernel_clone+0x60/0x2fe [<ffffffff80012f62>] kernel_thread+0x82/0xa0 [<ffffffff8003552c>] kthreadd+0x14a/0x1be [<ffffffff809357de>] ret_from_fork+0xe/0x1c Rewrite this function with apply_to_existing_page_range(). It is fine to not have any locking, because __kernel_map_pages() works with pages being allocated/deallocated and those pages are not changed by anyone else in the meantime. Fixes: 5fde3db5eb ("riscv: add ARCH_SUPPORTS_DEBUG_PAGEALLOC support") Signed-off-by: Nam Cao <namcao@linutronix.de> Cc: stable@vger.kernel.org Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/1289ecba9606a19917bc12b6c27da8aa23e1e5ae.1715750938.git.namcao@linutronix.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>		2024-05-22 09:15:09 -07:00
..
boot	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
configs	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
crypto	crypto: riscv - add vector crypto accelerated AES-CBC-CTS	2024-03-20 08:56:11 -07:00
errata	riscv: errata: Rename defines for Andes	2024-03-12 07:13:12 -07:00
include	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
kernel	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
kvm	KVM/riscv changes for 6.9	2024-03-11 10:10:48 -04:00
lib	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
mm	riscv: rewrite __kernel_map_pages() to fix sleeping in invalid context	2024-05-22 09:15:09 -07:00
net	bpf, riscv64/cfi: Support kCFI + BPF on riscv64	2024-03-06 15:18:16 -08:00
purgatory	riscv: Use SYM_*() assembly macros instead of deprecated ones	2023-11-06 09:42:47 -08:00
tools	riscv: Check relocations at compile time	2023-04-19 07:46:32 -07:00
Kbuild	RISC-V: hook new crypto subdir into build-system	2024-01-22 17:55:17 -08:00
Kconfig	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
Kconfig.debug	riscv: Add tests for riscv module loading	2023-11-07 14:59:32 -08:00
Kconfig.errata	RISC-V Patches for the 6.8 Merge Window, Part 4	2024-01-20 11:06:04 -08:00
Kconfig.socs	riscv: dts: Move BUILTIN_DTB_SOURCE to common Kconfig	2024-03-06 00:08:32 +00:00
Makefile	RISC-V: build: Allow LTO to be selected	2024-01-22 10:06:29 -08:00
Makefile.postlink	kbuild: remove ARCH_POSTLINK from module builds	2023-10-28 21:10:08 +09:00