bisecting cause commit starting from a581387e415bbb0085e7e67906c8f4a99746590e building syzkaller on 18d18b591b354e07ba76be8f115b7119d49056a9 testing commit a581387e415bbb0085e7e67906c8f4a99746590e with gcc (GCC) 8.1.0 kernel signature: f2dbe733e7cc8adc82f8c64f4f362c4ce1e457463ac99d8952f2e31182d1bca2 all runs: crashed: WARNING in __kernel_read testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 0c8fe6b327698c6def475827193cf7959cb782f1afeee98730120d1dc33f2b69 all runs: OK # git bisect start a581387e415bbb0085e7e67906c8f4a99746590e 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 Bisecting: 8468 revisions left to test after this (roughly 13 steps) [a0a4d17e02a80a74a63c7cbb7bc8cea2f0b7d8b1] Merge branch 'pcmcia-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux testing commit a0a4d17e02a80a74a63c7cbb7bc8cea2f0b7d8b1 with gcc (GCC) 8.1.0 kernel signature: 5d7a7159861ba1a0de837aaad326bd714b9d914f653357511ab3f7955254ffaf all runs: OK # git bisect good a0a4d17e02a80a74a63c7cbb7bc8cea2f0b7d8b1 Bisecting: 4245 revisions left to test after this (roughly 12 steps) [f558b8364e19f9222e7976c64e9367f66bab02cc] Merge tag 'driver-core-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core testing commit f558b8364e19f9222e7976c64e9367f66bab02cc with gcc (GCC) 8.1.0 kernel signature: c2d5cbfed12d1776b21b9df94cf4e6cd7a079ec398e0f4a2e6f9bccbc5ac7d9e all runs: basic kernel testing failed: BUG: using smp_processor_id() in preemptible code in ext4_mb_new_blocks # git bisect skip f558b8364e19f9222e7976c64e9367f66bab02cc Bisecting: 4245 revisions left to test after this (roughly 12 steps) [8beeae86b8e19a4714531f8764b68bd828ffba2a] mm/page_alloc: fix documentation error testing commit 8beeae86b8e19a4714531f8764b68bd828ffba2a with gcc (GCC) 8.1.0 kernel signature: 14a64722b3da6966fbc8ebd95158491b4d09d3aff5e0264777f99d9dd81d9d02 all runs: OK # git bisect good 8beeae86b8e19a4714531f8764b68bd828ffba2a Bisecting: 165 revisions left to test after this (roughly 7 steps) [a6bc851ffe0b246ab4f8aa0d01620fbc08d0441f] Merge tag 'tpmdd-next-v5.8-rc5' of git://git.infradead.org/users/jjs/linux-tpmdd testing commit a6bc851ffe0b246ab4f8aa0d01620fbc08d0441f with gcc (GCC) 8.1.0 kernel signature: 1dc40179c19cfb1761d453c45556fb273a866040932abe31591ef0a0952c30f8 all runs: OK # git bisect good a6bc851ffe0b246ab4f8aa0d01620fbc08d0441f Bisecting: 94 revisions left to test after this (roughly 6 steps) [d4e60453266b95b9dc19e0af2a819617e556bc4e] Restore gcc check in mips asm/unroll.h testing commit d4e60453266b95b9dc19e0af2a819617e556bc4e with gcc (GCC) 8.1.0 kernel signature: 81644fa4ac80d14821a2ff9c86f562425a5c84ef149581dec472b3c6a4579553 all runs: OK # git bisect good d4e60453266b95b9dc19e0af2a819617e556bc4e Bisecting: 53 revisions left to test after this (roughly 6 steps) [e8749d068855c2b075b3de1985e6af836a02b257] Merge tag 's390-5.8-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux testing commit e8749d068855c2b075b3de1985e6af836a02b257 with gcc (GCC) 8.1.0 kernel signature: 7e20151a062daca5cd4edb883f67b5257af2bfd5724664e0ff5c0b51a9801fca run #0: OK run #1: OK run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: boot failed: can't ssh into the instance # git bisect good e8749d068855c2b075b3de1985e6af836a02b257 Bisecting: 27 revisions left to test after this (roughly 5 steps) [3f8834327ae7d8bfc34793cfce72663af35133d0] Merge tag 'gpio-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio testing commit 3f8834327ae7d8bfc34793cfce72663af35133d0 with gcc (GCC) 8.1.0 kernel signature: 85c097218569e082034f9fa38510cb84ab0a6d8dd08c32bf46b17ffb3eb84354 all runs: OK # git bisect good 3f8834327ae7d8bfc34793cfce72663af35133d0 Bisecting: 16 revisions left to test after this (roughly 4 steps) [775802c0571fb438cd4f6548a323f9e4cb89f5aa] fs: remove __vfs_read testing commit 775802c0571fb438cd4f6548a323f9e4cb89f5aa with gcc (GCC) 8.1.0 kernel signature: 516af9fe5b666299ee23272bb67d41ff43ddb4267cb74852a3bcd7bd629e0c72 all runs: crashed: WARNING in __kernel_read # git bisect bad 775802c0571fb438cd4f6548a323f9e4cb89f5aa Bisecting: 4 revisions left to test after this (roughly 3 steps) [81238b2cff1469ff5b94390d026cd075105d6dcd] fs: implement kernel_write using __kernel_write testing commit 81238b2cff1469ff5b94390d026cd075105d6dcd with gcc (GCC) 8.1.0 kernel signature: 5baa94dbb2a4c5377e47a28cf95f1345373aad4e32b7a0cce148a42777d09270 all runs: OK # git bisect good 81238b2cff1469ff5b94390d026cd075105d6dcd Bisecting: 2 revisions left to test after this (roughly 1 step) [61a707c543e2afe3aa7e88f87267c5dafa4b5afa] fs: add a __kernel_read helper testing commit 61a707c543e2afe3aa7e88f87267c5dafa4b5afa with gcc (GCC) 8.1.0 kernel signature: 9463f2e70efcfa9be4e73c077eaa0622fae309d3b2f6ad00635ee0e734fa36ad all runs: OK # git bisect good 61a707c543e2afe3aa7e88f87267c5dafa4b5afa Bisecting: 0 revisions left to test after this (roughly 1 step) [6209dd9132e8ea5545cffc84483841e88ea8cc5b] fs: implement kernel_read using __kernel_read testing commit 6209dd9132e8ea5545cffc84483841e88ea8cc5b with gcc (GCC) 8.1.0 kernel signature: 099955aa3f11f65ceb6b1f0b712c635de3cc91bc83bfc0d2a5acf1ed18f6a3a3 all runs: crashed: WARNING in __kernel_read # git bisect bad 6209dd9132e8ea5545cffc84483841e88ea8cc5b Bisecting: 0 revisions left to test after this (roughly 0 steps) [a1f9b1c0439db47ea10418b8ee7092a0d970cc2d] integrity/ima: switch to using __kernel_read testing commit a1f9b1c0439db47ea10418b8ee7092a0d970cc2d with gcc (GCC) 8.1.0 kernel signature: 4526dbc0e2f3bd63fd59be0fcacebe05322bba04ad4181450728b6a09cd43dde all runs: OK # git bisect good a1f9b1c0439db47ea10418b8ee7092a0d970cc2d 6209dd9132e8ea5545cffc84483841e88ea8cc5b is the first bad commit commit 6209dd9132e8ea5545cffc84483841e88ea8cc5b Author: Christoph Hellwig Date: Fri May 8 09:00:28 2020 +0200 fs: implement kernel_read using __kernel_read Consolidate the two in-kernel read helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_read, and an access_ok check that doesn't make sense for kernel buffers to start with. Signed-off-by: Christoph Hellwig fs/read_write.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) culprit signature: 099955aa3f11f65ceb6b1f0b712c635de3cc91bc83bfc0d2a5acf1ed18f6a3a3 parent signature: 4526dbc0e2f3bd63fd59be0fcacebe05322bba04ad4181450728b6a09cd43dde revisions tested: 14, total time: 3h11m39.63475449s (build: 1h15m9.44070422s, test: 1h54m23.660891396s) first bad commit: 6209dd9132e8ea5545cffc84483841e88ea8cc5b fs: implement kernel_read using __kernel_read cc: ["hch@lst.de" "linux-fsdevel@vger.kernel.org" "linux-kernel@vger.kernel.org" "viro@zeniv.linux.org.uk"] crash: WARNING in __kernel_read ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2600 at fs/read_write.c:438 fsnotify_file include/linux/fsnotify.h:78 [inline] WARNING: CPU: 1 PID: 2600 at fs/read_write.c:438 fsnotify_access include/linux/fsnotify.h:249 [inline] WARNING: CPU: 1 PID: 2600 at fs/read_write.c:438 __kernel_read+0xf9/0x120 fs/read_write.c:449 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 2600 Comm: kworker/1:16 Not tainted 5.8.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_read_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xb3/0xec lib/dump_stack.c:118 panic+0x115/0x2fa kernel/panic.c:231 __warn.cold.13+0x20/0x25 kernel/panic.c:600 report_bug+0xc0/0xf0 lib/bug.c:198 handle_bug+0x35/0x90 arch/x86/kernel/traps.c:235 exc_invalid_op+0x13/0x60 arch/x86/kernel/traps.c:255 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:542 RIP: 0010:__kernel_read+0xf9/0x120 fs/read_write.c:438 Code: 8b 04 25 00 7f 01 00 48 01 a8 98 10 00 00 eb 8e 45 31 c9 45 31 c0 b9 01 00 00 00 4c 89 f2 89 de 4c 89 e7 e8 29 99 05 00 eb d4 <0f> 0b 48 c7 c5 ea ff ff ff e9 77 ff ff ff 48 c7 c5 ea ff ff ff e9 RSP: 0018:ffffc9000538fdf8 EFLAGS: 00010246 RAX: 00000000081d801e RBX: ffff888129340680 RCX: ffffc9000538fe28 RDX: 0000000000000007 RSI: ffff88810e55e260 RDI: ffff88811ebcec00 RBP: ffff88810e55e210 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff846b2534 R11: eaeb4e6b42d1966d R12: ffffffffffffffff R13: 0000000000000000 R14: ffff88810e55e330 R15: ffff88810e55e338 p9_fd_read net/9p/trans_fd.c:263 [inline] p9_read_work+0xa2/0x370 net/9p/trans_fd.c:298 process_one_work+0x26a/0x5f0 kernel/workqueue.c:2269 worker_thread+0x38/0x380 kernel/workqueue.c:2415 kthread+0x148/0x170 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Kernel Offset: disabled Rebooting in 86400 seconds..