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charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 02B59120016 X-Rspam-User: X-Stat-Signature: d9ujiet1x883gi7349ihub87sgbz6xze X-Rspamd-Server: rspam09 X-HE-Tag: 1755006606-734502 X-HE-Meta: U2FsdGVkX19H81krf4lnOu9wqSEwNvBNmla9NIrOGnsb3vEI1c20SXghR/D9K0HOT/Alo8e6xplxLOkd268ill47fNLSJprQXciC6KMMoQWULidSLGvNnr8QYKGmpk55+k+eXfxnYxvlgUDbGVjQswBFb4g4CRTICqnuwrw8SucVGlI4GItQPy/jA0fNjUUzdvYZykxgQfpXuXfKmVTgCWBqCU3y6rhEViCN5qIceyitNkuvECBaOaGBSU5i0ytHHctV6N9RPtAGAw+AgDaR5qnb+a/Lp+PTIMFIMn8XC1S+vw6KN7MJtqZAoNqOW/zVaRw4+zbBmgBe9k6AfHzb3LzAUqPEcRMj2yUwQiwdUbibh6LzwLV8ThI9JZpvdnZiTTiwuw8ybtTl5ZUuNtbAErEOdHb197Ck09hdfFut0/WqVOKylZal06Y1Ky2GPo0/3bfVvhb+MhR4OhGmlzzINe3LRIIqnyBzsh9fQUHWKpF2An0XlFyxbC+L2b5bEypCGPbHthmX3cn8VWK9zZ7P+i8wvL7oRh8wMOQaIG9YvXad105K2b1cgRZZ5fQaLsBHHd/lxWmVWyb6rsaPTF7smuyh/CYwmxMjovzRx8i031sWhhF7i8X70S8gAxwqYYBLNCTDcZhaps4Ihr42g8uhrC/0wo7S4P9TjcdvFU54l1rUYWuEt0dZqElJjSWkn3u8wg57EVJoBTR2rsezDvMd/k2rMda1SU1/lm5YNagwnGBHzZwTXtNcLyNPtTzpE/0zqQsOJobsNwT5ySIJTBLiZauHi7WBuUeG+GzyU1eATNvML+ZKtRr9FXMd+ctdGbMlNTSjKFjEvgKc6K8YUCdPGQ1vARQXxxZJ5AQHy9xFHdI6CxlqaBTHMoRLhJGvXmt/vhGAjUYvWgkY4NksoxN+WHk34t+InabeoCCLwwT+uGTf+Y7ZQRkyk0k/7h1njpFCrpdz8MRkl/v9huCvnqJ njddGC78 ZM/rZ/yeHt9iKX/E82VLDoY7gIR02Xta4O/IrQl/p8fBfB5QJSXbg85J0YaPFPSYuTOFfL8lsrD5E/6rr8iok7ied5CH5+RKavGRO X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 08/12/25 at 09:34pm, Baoquan He wrote: > alexghiti@rivosinc.com, agordeev@linux.ibm.com, linux@armlinux.org.uk, > linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, > linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, > x86@kernel.org, chris@zankel.net, jcmvbkbc@gmail.com, linux-um@lists.infradead.org > Cc: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, > dvyukov@google.com, vincenzo.frascino@arm.com, > akpm@linux-foundation.org, kasan-dev@googlegroups.com, > linux-kernel@vger.kernel.org, kexec@lists.infradead.org, > sj@kernel.org, lorenzo.stoakes@oracle.com, elver@google.com, > snovitoll@gmail.com > Bcc: bhe@redhat.com > Subject: Re: [PATCH v2 00/12] mm/kasan: make kasan=on|off work for all three > modes > Reply-To: > In-Reply-To: <20250812124941.69508-1-bhe@redhat.com> > > Forgot adding related ARCH mailing list or people to CC, add them. Sorry for the noise, I made mistake on mail format when adding people to CC. > > On 08/12/25 at 08:49pm, Baoquan He wrote: > > Currently only hw_tags mode of kasan can be enabled or disabled with > > kernel parameter kasan=on|off for built kernel. For kasan generic and > > sw_tags mode, there's no way to disable them once kernel is built. > > This is not convenient sometime, e.g in system kdump is configured. > > When the 1st kernel has KASAN enabled and crash triggered to switch to > > kdump kernel, the generic or sw_tags mode will cost much extra memory > > for kasan shadow while in fact it's meaningless to have kasan in kdump > > kernel. > > > > So this patchset moves the kasan=on|off out of hw_tags scope and into > > common code to make it visible in generic and sw_tags mode too. Then we > > can add kasan=off in kdump kernel to reduce the unneeded meomry cost for > > kasan. > > > > Changelog: > > ==== > > v1->v2: > > - Add __ro_after_init for __ro_after_init, and remove redundant blank > > lines in mm/kasan/common.c. Thanks to Marco. > > - Fix a code bug in when CONFIG_KASAN is unset, > > this is found out by SeongJae and Lorenzo, and also reported by LKP > > report, thanks to them. > > - Add a missing kasan_enabled() checking in kasan_report(). This will > > cause below KASAN report info even though kasan=off is set: > > ================================================================== > > BUG: KASAN: stack-out-of-bounds in tick_program_event+0x130/0x150 > > Read of size 4 at addr ffff00005f747778 by task swapper/0/1 > > > > CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.16.0+ #8 PREEMPT(voluntary) > > Hardware name: GIGABYTE R272-P30-JG/MP32-AR0-JG, BIOS F31n (SCP: 2.10.20220810) 09/30/2022 > > Call trace: > > show_stack+0x30/0x90 (C) > > dump_stack_lvl+0x7c/0xa0 > > print_address_description.constprop.0+0x90/0x310 > > print_report+0x104/0x1f0 > > kasan_report+0xc8/0x110 > > __asan_report_load4_noabort+0x20/0x30 > > tick_program_event+0x130/0x150 > > ......snip... > > ================================================================== > > > > - Add jump_label_init() calling before kasan_init() in setup_arch() in these > > architectures: xtensa, arm. Because they currenly rely on > > jump_label_init() in main() which is a little late. Then the early static > > key kasan_flag_enabled in kasan_init() won't work. > > > > - In UML architecture, change to enable kasan_flag_enabled in arch_mm_preinit() > > because kasan_init() is enabled before main(), there's no chance to operate > > on static key in kasan_init(). > > > > Test: > > ===== > > In v1, I took test on x86_64 for generic mode, and on arm64 for > > generic, sw_tags and hw_tags mode. All of them works well. > > > > In v2, I only tested on arm64 for generic, sw_tags and hw_tags mode, it > > works. For powerpc, I got a BOOK3S/64 machine, while it says > > 'KASAN not enabled as it requires radix' and KASAN is disabled. Will > > look for other POWER machine to test this. > > ==== > > > > Baoquan He (12): > > mm/kasan: add conditional checks in functions to return directly if > > kasan is disabled > > mm/kasan: move kasan= code to common place > > mm/kasan/sw_tags: don't initialize kasan if it's disabled > > arch/arm: don't initialize kasan if it's disabled > > arch/arm64: don't initialize kasan if it's disabled > > arch/loongarch: don't initialize kasan if it's disabled > > arch/powerpc: don't initialize kasan if it's disabled > > arch/riscv: don't initialize kasan if it's disabled > > arch/x86: don't initialize kasan if it's disabled > > arch/xtensa: don't initialize kasan if it's disabled > > arch/um: don't initialize kasan if it's disabled > > mm/kasan: make kasan=on|off take effect for all three modes > > > > arch/arm/kernel/setup.c | 6 +++++ > > arch/arm/mm/kasan_init.c | 6 +++++ > > arch/arm64/mm/kasan_init.c | 7 ++++++ > > arch/loongarch/mm/kasan_init.c | 5 ++++ > > arch/powerpc/mm/kasan/init_32.c | 8 +++++- > > arch/powerpc/mm/kasan/init_book3e_64.c | 6 +++++ > > arch/powerpc/mm/kasan/init_book3s_64.c | 6 +++++ > > arch/riscv/mm/kasan_init.c | 6 +++++ > > arch/um/kernel/mem.c | 6 +++++ > > arch/x86/mm/kasan_init_64.c | 6 +++++ > > arch/xtensa/kernel/setup.c | 1 + > > arch/xtensa/mm/kasan_init.c | 6 +++++ > > include/linux/kasan-enabled.h | 18 ++++++------- > > mm/kasan/common.c | 25 ++++++++++++++++++ > > mm/kasan/generic.c | 20 +++++++++++++-- > > mm/kasan/hw_tags.c | 35 ++------------------------ > > mm/kasan/init.c | 6 +++++ > > mm/kasan/quarantine.c | 3 +++ > > mm/kasan/report.c | 4 ++- > > mm/kasan/shadow.c | 23 ++++++++++++++++- > > mm/kasan/sw_tags.c | 9 +++++++ > > 21 files changed, 165 insertions(+), 47 deletions(-) > > > > -- > > 2.41.0 > > > >