| Message ID | 20241008101526.2591147-1-snovitoll@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3] mm, kasan, kmsan: copy_from/to_kernel_nofault | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Tue, 8 Oct 2024 at 12:14, Sabyrzhan Tasbolatov <snovitoll@gmail.com> wrote: > > Instrument copy_from_kernel_nofault() with KMSAN for uninitialized kernel > memory check and copy_to_kernel_nofault() with KASAN, KCSAN to detect > the memory corruption. > > syzbot reported that bpf_probe_read_kernel() kernel helper triggered > KASAN report via kasan_check_range() which is not the expected behaviour > as copy_from_kernel_nofault() is meant to be a non-faulting helper. > > Solution is, suggested by Marco Elver, to replace KASAN, KCSAN check in > copy_from_kernel_nofault() with KMSAN detection of copying uninitilaized > kernel memory. In copy_to_kernel_nofault() we can retain > instrument_write() explicitly for the memory corruption instrumentation. > > copy_to_kernel_nofault() is tested on x86_64 and arm64 with > CONFIG_KASAN_SW_TAGS. On arm64 with CONFIG_KASAN_HW_TAGS, > kunit test currently fails. Need more clarification on it > - currently, disabled in kunit test. I assume you retested. Did you also test the bpf_probe_read_kernel() false positive no longer appears? > Link: https://lore.kernel.org/linux-mm/CANpmjNMAVFzqnCZhEity9cjiqQ9CVN1X7qeeeAp_6yKjwKo8iw@mail.gmail.com/ > Suggested-by: Marco Elver <elver@google.com> This looks more reasonable: Reviewed-by: Marco Elver <elver@google.com> This looks like the most conservative thing to do for now. > Reported-by: syzbot+61123a5daeb9f7454599@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599 > Reported-by: Andrey Konovalov <andreyknvl@gmail.com> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505 > Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> > --- > v2: > - squashed previous submitted in -mm tree 2 patches based on Linus tree > v3: > - moved checks to *_nofault_loop macros per Marco's comments > - edited the commit message > --- > mm/kasan/kasan_test_c.c | 27 +++++++++++++++++++++++++++ > mm/kmsan/kmsan_test.c | 17 +++++++++++++++++ > mm/maccess.c | 10 ++++++++-- > 3 files changed, 52 insertions(+), 2 deletions(-) > > diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c > index a181e4780d9d..5cff90f831db 100644 > --- a/mm/kasan/kasan_test_c.c > +++ b/mm/kasan/kasan_test_c.c > @@ -1954,6 +1954,32 @@ static void rust_uaf(struct kunit *test) > KUNIT_EXPECT_KASAN_FAIL(test, kasan_test_rust_uaf()); > } > > +static void copy_to_kernel_nofault_oob(struct kunit *test) > +{ > + char *ptr; > + char buf[128]; > + size_t size = sizeof(buf); > + > + /* Not detecting fails currently with HW_TAGS */ > + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); > + > + ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL); > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); > + OPTIMIZER_HIDE_VAR(ptr); > + > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) { > + /* Check that the returned pointer is tagged. */ > + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); > + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); > + } > + > + KUNIT_EXPECT_KASAN_FAIL(test, > + copy_to_kernel_nofault(&buf[0], ptr, size)); > + KUNIT_EXPECT_KASAN_FAIL(test, > + copy_to_kernel_nofault(ptr, &buf[0], size)); > + kfree(ptr); > +} > + > static struct kunit_case kasan_kunit_test_cases[] = { > KUNIT_CASE(kmalloc_oob_right), > KUNIT_CASE(kmalloc_oob_left), > @@ -2027,6 +2053,7 @@ static struct kunit_case kasan_kunit_test_cases[] = { > KUNIT_CASE(match_all_not_assigned), > KUNIT_CASE(match_all_ptr_tag), > KUNIT_CASE(match_all_mem_tag), > + KUNIT_CASE(copy_to_kernel_nofault_oob), > KUNIT_CASE(rust_uaf), > {} > }; > diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c > index 13236d579eba..9733a22c46c1 100644 > --- a/mm/kmsan/kmsan_test.c > +++ b/mm/kmsan/kmsan_test.c > @@ -640,6 +640,22 @@ static void test_unpoison_memory(struct kunit *test) > KUNIT_EXPECT_TRUE(test, report_matches(&expect)); > } > > +static void test_copy_from_kernel_nofault(struct kunit *test) > +{ > + long ret; > + char buf[4], src[4]; > + size_t size = sizeof(buf); > + > + EXPECTATION_UNINIT_VALUE_FN(expect, "copy_from_kernel_nofault"); > + kunit_info( > + test, > + "testing copy_from_kernel_nofault with uninitialized memory\n"); > + > + ret = copy_from_kernel_nofault((char *)&buf[0], (char *)&src[0], size); > + USE(ret); > + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); > +} > + > static struct kunit_case kmsan_test_cases[] = { > KUNIT_CASE(test_uninit_kmalloc), > KUNIT_CASE(test_init_kmalloc), > @@ -664,6 +680,7 @@ static struct kunit_case kmsan_test_cases[] = { > KUNIT_CASE(test_long_origin_chain), > KUNIT_CASE(test_stackdepot_roundtrip), > KUNIT_CASE(test_unpoison_memory), > + KUNIT_CASE(test_copy_from_kernel_nofault), > {}, > }; > > diff --git a/mm/maccess.c b/mm/maccess.c > index 518a25667323..3ca55ec63a6a 100644 > --- a/mm/maccess.c > +++ b/mm/maccess.c > @@ -13,9 +13,14 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src, > return true; > } > > +/* > + * The below only uses kmsan_check_memory() to ensure uninitialized kernel > + * memory isn't leaked. > + */ > #define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \ > while (len >= sizeof(type)) { \ > - __get_kernel_nofault(dst, src, type, err_label); \ > + __get_kernel_nofault(dst, src, type, err_label); \ > + kmsan_check_memory(src, sizeof(type)); \ > dst += sizeof(type); \ > src += sizeof(type); \ > len -= sizeof(type); \ > @@ -49,7 +54,8 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); > > #define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \ > while (len >= sizeof(type)) { \ > - __put_kernel_nofault(dst, src, type, err_label); \ > + __put_kernel_nofault(dst, src, type, err_label); \ > + instrument_write(dst, sizeof(type)); \ > dst += sizeof(type); \ > src += sizeof(type); \ > len -= sizeof(type); \ > -- > 2.34.1 >
On Tue, Oct 8, 2024 at 4:36 PM Marco Elver <elver@google.com> wrote: > > On Tue, 8 Oct 2024 at 12:14, Sabyrzhan Tasbolatov <snovitoll@gmail.com> wrote: > > > > Instrument copy_from_kernel_nofault() with KMSAN for uninitialized kernel > > memory check and copy_to_kernel_nofault() with KASAN, KCSAN to detect > > the memory corruption. > > > > syzbot reported that bpf_probe_read_kernel() kernel helper triggered > > KASAN report via kasan_check_range() which is not the expected behaviour > > as copy_from_kernel_nofault() is meant to be a non-faulting helper. > > > > Solution is, suggested by Marco Elver, to replace KASAN, KCSAN check in > > copy_from_kernel_nofault() with KMSAN detection of copying uninitilaized > > kernel memory. In copy_to_kernel_nofault() we can retain > > instrument_write() explicitly for the memory corruption instrumentation. > > > > copy_to_kernel_nofault() is tested on x86_64 and arm64 with > > CONFIG_KASAN_SW_TAGS. On arm64 with CONFIG_KASAN_HW_TAGS, > > kunit test currently fails. Need more clarification on it > > - currently, disabled in kunit test. > > I assume you retested. Did you also test the bpf_probe_read_kernel() > false positive no longer appears? I've tested on: - x86_64 with KMSAN - x86_64 with KASAN - arm64 with HW_TAGS -- still failing - arm64 with SW_TAGS Please see the testing result in the following link: https://gist.github.com/novitoll/e2ccb2162340f7f8a63b63ee3e0f9994 I've also tested bpf_probe_read_kernel() in x86_64 KMSAN build, it does trigger KMSAN, though I don't see explicitly copy_from_kernel* in stack frame. AFAIU, it's checked prior to it in text_poke_copy(). Attached the PoC in the comment of the link above: root@syzkaller:/tmp# uname -a Linux syzkaller 6.12.0-rc2-g441b500abd70 #10 SMP PREEMPT_DYNAMIC Wed Oct 9 00:17:59 +05 2024 x86_64 GNU/Linux root@syzkaller:/tmp# ./exploit [*] exploit start [+] program loaded! [ 139.778255] ===================================================== [ 139.778846] BUG: KMSAN: uninit-value in bcmp+0x155/0x290 [ 139.779311] bcmp+0x155/0x290 [ 139.779591] __text_poke+0xe2d/0x1120 [ 139.779950] text_poke_copy+0x1e7/0x2b0 [ 139.780297] bpf_arch_text_copy+0x41/0xa0 [ 139.780665] bpf_dispatcher_change_prog+0x12dd/0x16b0 [ 139.781324] bpf_prog_test_run_xdp+0xbf0/0x1d20 [ 139.781898] bpf_prog_test_run+0x5d6/0x9a0 [ 139.782372] __sys_bpf+0x758/0xf10 [ 139.782759] __x64_sys_bpf+0xdd/0x130 [ 139.783178] x64_sys_call+0x1a21/0x4e10 [ 139.783610] do_syscall_64+0xcd/0x1b0 [ 139.784039] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 139.784597] [ 139.784779] Uninit was created at: [ 139.785197] __alloc_pages_noprof+0x717/0xe70 [ 139.785689] alloc_pages_bulk_noprof+0x17e1/0x20e0 [ 139.786223] alloc_pages_bulk_array_mempolicy_noprof+0x49e/0x5b0 [ 139.786873] __vmalloc_node_range_noprof+0xef2/0x24f0 [ 139.787414] execmem_alloc+0x1ec/0x4c0 [ 139.787841] bpf_jit_alloc_exec+0x3e/0x40 [ 139.788299] bpf_dispatcher_change_prog+0x430/0x16b0 [ 139.788837] bpf_prog_test_run_xdp+0xbf0/0x1d20 [ 139.789324] bpf_prog_test_run+0x5d6/0x9a0 [ 139.789774] __sys_bpf+0x758/0xf10 [ 139.790167] __x64_sys_bpf+0xdd/0x130 [ 139.790580] x64_sys_call+0x1a21/0x4e10 [ 139.791007] do_syscall_64+0xcd/0x1b0 [ 139.791423] entry_SYSCALL_64_after_hwframe+0x67/0x6f > > > Link: https://lore.kernel.org/linux-mm/CANpmjNMAVFzqnCZhEity9cjiqQ9CVN1X7qeeeAp_6yKjwKo8iw@mail.gmail.com/ > > Suggested-by: Marco Elver <elver@google.com> > > This looks more reasonable: > > Reviewed-by: Marco Elver <elver@google.com> > > This looks like the most conservative thing to do for now. Done. > > > Reported-by: syzbot+61123a5daeb9f7454599@syzkaller.appspotmail.com > > Closes: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599 > > Reported-by: Andrey Konovalov <andreyknvl@gmail.com> > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505 > > Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> > > --- > > v2: > > - squashed previous submitted in -mm tree 2 patches based on Linus tree > > v3: > > - moved checks to *_nofault_loop macros per Marco's comments > > - edited the commit message > > --- > > mm/kasan/kasan_test_c.c | 27 +++++++++++++++++++++++++++ > > mm/kmsan/kmsan_test.c | 17 +++++++++++++++++ > > mm/maccess.c | 10 ++++++++-- > > 3 files changed, 52 insertions(+), 2 deletions(-) > > > > diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c > > index a181e4780d9d..5cff90f831db 100644 > > --- a/mm/kasan/kasan_test_c.c > > +++ b/mm/kasan/kasan_test_c.c > > @@ -1954,6 +1954,32 @@ static void rust_uaf(struct kunit *test) > > KUNIT_EXPECT_KASAN_FAIL(test, kasan_test_rust_uaf()); > > } > > > > +static void copy_to_kernel_nofault_oob(struct kunit *test) > > +{ > > + char *ptr; > > + char buf[128]; > > + size_t size = sizeof(buf); > > + > > + /* Not detecting fails currently with HW_TAGS */ > > + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); > > + > > + ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL); > > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); > > + OPTIMIZER_HIDE_VAR(ptr); > > + > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) { > > + /* Check that the returned pointer is tagged. */ > > + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); > > + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); > > + } > > + > > + KUNIT_EXPECT_KASAN_FAIL(test, > > + copy_to_kernel_nofault(&buf[0], ptr, size)); > > + KUNIT_EXPECT_KASAN_FAIL(test, > > + copy_to_kernel_nofault(ptr, &buf[0], size)); > > + kfree(ptr); > > +} > > + > > static struct kunit_case kasan_kunit_test_cases[] = { > > KUNIT_CASE(kmalloc_oob_right), > > KUNIT_CASE(kmalloc_oob_left), > > @@ -2027,6 +2053,7 @@ static struct kunit_case kasan_kunit_test_cases[] = { > > KUNIT_CASE(match_all_not_assigned), > > KUNIT_CASE(match_all_ptr_tag), > > KUNIT_CASE(match_all_mem_tag), > > + KUNIT_CASE(copy_to_kernel_nofault_oob), > > KUNIT_CASE(rust_uaf), > > {} > > }; > > diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c > > index 13236d579eba..9733a22c46c1 100644 > > --- a/mm/kmsan/kmsan_test.c > > +++ b/mm/kmsan/kmsan_test.c > > @@ -640,6 +640,22 @@ static void test_unpoison_memory(struct kunit *test) > > KUNIT_EXPECT_TRUE(test, report_matches(&expect)); > > } > > > > +static void test_copy_from_kernel_nofault(struct kunit *test) > > +{ > > + long ret; > > + char buf[4], src[4]; > > + size_t size = sizeof(buf); > > + > > + EXPECTATION_UNINIT_VALUE_FN(expect, "copy_from_kernel_nofault"); > > + kunit_info( > > + test, > > + "testing copy_from_kernel_nofault with uninitialized memory\n"); > > + > > + ret = copy_from_kernel_nofault((char *)&buf[0], (char *)&src[0], size); > > + USE(ret); > > + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); > > +} > > + > > static struct kunit_case kmsan_test_cases[] = { > > KUNIT_CASE(test_uninit_kmalloc), > > KUNIT_CASE(test_init_kmalloc), > > @@ -664,6 +680,7 @@ static struct kunit_case kmsan_test_cases[] = { > > KUNIT_CASE(test_long_origin_chain), > > KUNIT_CASE(test_stackdepot_roundtrip), > > KUNIT_CASE(test_unpoison_memory), > > + KUNIT_CASE(test_copy_from_kernel_nofault), > > {}, > > }; > > > > diff --git a/mm/maccess.c b/mm/maccess.c > > index 518a25667323..3ca55ec63a6a 100644 > > --- a/mm/maccess.c > > +++ b/mm/maccess.c > > @@ -13,9 +13,14 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src, > > return true; > > } > > > > +/* > > + * The below only uses kmsan_check_memory() to ensure uninitialized kernel > > + * memory isn't leaked. > > + */ > > #define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \ > > while (len >= sizeof(type)) { \ > > - __get_kernel_nofault(dst, src, type, err_label); \ > > + __get_kernel_nofault(dst, src, type, err_label); \ > > + kmsan_check_memory(src, sizeof(type)); \ > > dst += sizeof(type); \ > > src += sizeof(type); \ > > len -= sizeof(type); \ > > @@ -49,7 +54,8 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); > > > > #define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \ > > while (len >= sizeof(type)) { \ > > - __put_kernel_nofault(dst, src, type, err_label); \ > > + __put_kernel_nofault(dst, src, type, err_label); \ > > + instrument_write(dst, sizeof(type)); \ > > dst += sizeof(type); \ > > src += sizeof(type); \ > > len -= sizeof(type); \ > > -- > > 2.34.1 > >
diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c index a181e4780d9d..5cff90f831db 100644 --- a/mm/kasan/kasan_test_c.c +++ b/mm/kasan/kasan_test_c.c @@ -1954,6 +1954,32 @@ static void rust_uaf(struct kunit *test) KUNIT_EXPECT_KASAN_FAIL(test, kasan_test_rust_uaf()); } +static void copy_to_kernel_nofault_oob(struct kunit *test) +{ + char *ptr; + char buf[128]; + size_t size = sizeof(buf); + + /* Not detecting fails currently with HW_TAGS */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); + + ptr = kmalloc(size - KASAN_GRANULE_SIZE, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); + + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) { + /* Check that the returned pointer is tagged. */ + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + } + + KUNIT_EXPECT_KASAN_FAIL(test, + copy_to_kernel_nofault(&buf[0], ptr, size)); + KUNIT_EXPECT_KASAN_FAIL(test, + copy_to_kernel_nofault(ptr, &buf[0], size)); + kfree(ptr); +} + static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(kmalloc_oob_right), KUNIT_CASE(kmalloc_oob_left), @@ -2027,6 +2053,7 @@ static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(match_all_not_assigned), KUNIT_CASE(match_all_ptr_tag), KUNIT_CASE(match_all_mem_tag), + KUNIT_CASE(copy_to_kernel_nofault_oob), KUNIT_CASE(rust_uaf), {} }; diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c index 13236d579eba..9733a22c46c1 100644 --- a/mm/kmsan/kmsan_test.c +++ b/mm/kmsan/kmsan_test.c @@ -640,6 +640,22 @@ static void test_unpoison_memory(struct kunit *test) KUNIT_EXPECT_TRUE(test, report_matches(&expect)); } +static void test_copy_from_kernel_nofault(struct kunit *test) +{ + long ret; + char buf[4], src[4]; + size_t size = sizeof(buf); + + EXPECTATION_UNINIT_VALUE_FN(expect, "copy_from_kernel_nofault"); + kunit_info( + test, + "testing copy_from_kernel_nofault with uninitialized memory\n"); + + ret = copy_from_kernel_nofault((char *)&buf[0], (char *)&src[0], size); + USE(ret); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + static struct kunit_case kmsan_test_cases[] = { KUNIT_CASE(test_uninit_kmalloc), KUNIT_CASE(test_init_kmalloc), @@ -664,6 +680,7 @@ static struct kunit_case kmsan_test_cases[] = { KUNIT_CASE(test_long_origin_chain), KUNIT_CASE(test_stackdepot_roundtrip), KUNIT_CASE(test_unpoison_memory), + KUNIT_CASE(test_copy_from_kernel_nofault), {}, }; diff --git a/mm/maccess.c b/mm/maccess.c index 518a25667323..3ca55ec63a6a 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -13,9 +13,14 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src, return true; } +/* + * The below only uses kmsan_check_memory() to ensure uninitialized kernel + * memory isn't leaked. + */ #define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \ while (len >= sizeof(type)) { \ - __get_kernel_nofault(dst, src, type, err_label); \ + __get_kernel_nofault(dst, src, type, err_label); \ + kmsan_check_memory(src, sizeof(type)); \ dst += sizeof(type); \ src += sizeof(type); \ len -= sizeof(type); \ @@ -49,7 +54,8 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); #define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \ while (len >= sizeof(type)) { \ - __put_kernel_nofault(dst, src, type, err_label); \ + __put_kernel_nofault(dst, src, type, err_label); \ + instrument_write(dst, sizeof(type)); \ dst += sizeof(type); \ src += sizeof(type); \ len -= sizeof(type); \
Instrument copy_from_kernel_nofault() with KMSAN for uninitialized kernel memory check and copy_to_kernel_nofault() with KASAN, KCSAN to detect the memory corruption. syzbot reported that bpf_probe_read_kernel() kernel helper triggered KASAN report via kasan_check_range() which is not the expected behaviour as copy_from_kernel_nofault() is meant to be a non-faulting helper. Solution is, suggested by Marco Elver, to replace KASAN, KCSAN check in copy_from_kernel_nofault() with KMSAN detection of copying uninitilaized kernel memory. In copy_to_kernel_nofault() we can retain instrument_write() explicitly for the memory corruption instrumentation. copy_to_kernel_nofault() is tested on x86_64 and arm64 with CONFIG_KASAN_SW_TAGS. On arm64 with CONFIG_KASAN_HW_TAGS, kunit test currently fails. Need more clarification on it - currently, disabled in kunit test. Link: https://lore.kernel.org/linux-mm/CANpmjNMAVFzqnCZhEity9cjiqQ9CVN1X7qeeeAp_6yKjwKo8iw@mail.gmail.com/ Suggested-by: Marco Elver <elver@google.com> Reported-by: syzbot+61123a5daeb9f7454599@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599 Reported-by: Andrey Konovalov <andreyknvl@gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505 Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> --- v2: - squashed previous submitted in -mm tree 2 patches based on Linus tree v3: - moved checks to *_nofault_loop macros per Marco's comments - edited the commit message --- mm/kasan/kasan_test_c.c | 27 +++++++++++++++++++++++++++ mm/kmsan/kmsan_test.c | 17 +++++++++++++++++ mm/maccess.c | 10 ++++++++-- 3 files changed, 52 insertions(+), 2 deletions(-)