* [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio @ 2022-06-28 22:59 syzbot 2022-06-29 4:41 ` Eric Biggers 0 siblings, 1 reply; 7+ messages in thread From: syzbot @ 2022-06-28 22:59 UTC (permalink / raw) To: akpm, linux-fsdevel, linux-kernel, linux-mm, syzkaller-bugs, willy Hello, syzbot found the following issue on: HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com BUG: unable to handle page fault for address: ffff888021f7e005 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> zero_user_segments include/linux/highmem.h:272 [inline] folio_zero_range include/linux/highmem.h:428 [inline] truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 truncate_inode_pages mm/truncate.c:452 [inline] truncate_pagecache+0x63/0x90 mm/truncate.c:753 simple_setattr+0xed/0x110 fs/libfs.c:535 secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 notify_change+0xb8c/0x12b0 fs/attr.c:424 do_truncate+0x13c/0x200 fs/open.c:65 do_sys_ftruncate+0x536/0x730 fs/open.c:193 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fb29d900899 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 </TASK> Modules linked in: CR2: ffff888021f7e005 ---[ end trace 0000000000000000 ]--- RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: c1 e9 03 shr $0x3,%ecx 3: 40 0f b6 f6 movzbl %sil,%esi 7: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax e: 01 01 01 11: 48 0f af c6 imul %rsi,%rax 15: f3 48 ab rep stos %rax,%es:(%rdi) 18: 89 d1 mov %edx,%ecx 1a: f3 aa rep stos %al,%es:(%rdi) 1c: 4c 89 c8 mov %r9,%rax 1f: c3 retq 20: 90 nop 21: 49 89 f9 mov %rdi,%r9 24: 40 88 f0 mov %sil,%al 27: 48 89 d1 mov %rdx,%rcx * 2a: f3 aa rep stos %al,%es:(%rdi) <-- trapping instruction 2c: 4c 89 c8 mov %r9,%rax 2f: c3 retq 30: 90 nop 31: 49 89 fa mov %rdi,%r10 34: 40 0f b6 ce movzbl %sil,%ecx 38: 48 rex.W 39: b8 01 01 01 01 mov $0x1010101,%eax 3e: 01 01 add %eax,(%rcx) --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio 2022-06-28 22:59 [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio syzbot @ 2022-06-29 4:41 ` Eric Biggers 2022-06-29 16:30 ` Axel Rasmussen 0 siblings, 1 reply; 7+ messages in thread From: Eric Biggers @ 2022-06-29 4:41 UTC (permalink / raw) To: Mike Rapoport, Axel Rasmussen Cc: akpm, linux-fsdevel, linux-kernel, linux-mm, syzkaller-bugs, syzbot, willy On Tue, Jun 28, 2022 at 03:59:26PM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 > kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 > dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > > BUG: unable to handle page fault for address: ffff888021f7e005 > #PF: supervisor write access in kernel mode > #PF: error_code(0x0002) - not-present page > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > Oops: 0002 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > zero_user_segments include/linux/highmem.h:272 [inline] > folio_zero_range include/linux/highmem.h:428 [inline] > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > truncate_inode_pages mm/truncate.c:452 [inline] > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > simple_setattr+0xed/0x110 fs/libfs.c:535 > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > notify_change+0xb8c/0x12b0 fs/attr.c:424 > do_truncate+0x13c/0x200 fs/open.c:65 > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > RIP: 0033:0x7fb29d900899 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > </TASK> > Modules linked in: > CR2: ffff888021f7e005 > ---[ end trace 0000000000000000 ]--- I think this is a bug in memfd_secret. secretmem_setattr() can race with a page being faulted in by secretmem_fault(). Specifically, a page can be faulted in after secretmem_setattr() has set i_size but before it zeroes out the partial page past i_size. memfd_secret pages aren't mapped in the kernel direct map, so the crash occurs when the kernel tries to zero out the partial page. I don't know what the best solution is -- maybe a rw_semaphore protecting secretmem_fault() and secretmem_setattr()? Or perhaps secretmem_setattr() should avoid the call to truncate_setsize() by not using simple_setattr(), given that secretmem_setattr() only supports the size going from zero to nonzero. The following commit tried to fix a similar bug, but it wasn't enough: commit f9b141f93659e09a52e28791ccbaf69c273b8e92 Author: Axel Rasmussen <axelrasmussen@google.com> Date: Thu Apr 14 19:13:31 2022 -0700 mm/secretmem: fix panic when growing a memfd_secret Here's a simplified reproducer. Note, for memfd_secret to be supported, the kernel config must contain CONFIG_SECRETMEM=y and the kernel command line must contain secretmem.enable=1. #include <pthread.h> #include <setjmp.h> #include <signal.h> #include <sys/mman.h> #include <sys/syscall.h> #include <unistd.h> static volatile int fd; static jmp_buf jump_buf; static void *truncate_thread(void *arg) { for (;;) ftruncate(fd, 1000); } static void handle_sigbus(int sig) { longjmp(jump_buf, 1); } int main(void) { struct sigaction act = { .sa_handler = handle_sigbus, .sa_flags = SA_NODEFER, }; pthread_t t; void *addr; sigaction(SIGBUS, &act, NULL); pthread_create(&t, NULL, truncate_thread, NULL); for (;;) { fd = syscall(__NR_memfd_secret, 0); addr = mmap(NULL, 8192, PROT_WRITE, MAP_SHARED, fd, 0); if (setjmp(jump_buf) == 0) *(unsigned int *)addr = 0; munmap(addr, 8192); close(fd); } } ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio 2022-06-29 4:41 ` Eric Biggers @ 2022-06-29 16:30 ` Axel Rasmussen 2022-06-30 8:47 ` Mike Rapoport [not found] ` <20220701073241.1277-1-hdanton@sina.com> 0 siblings, 2 replies; 7+ messages in thread From: Axel Rasmussen @ 2022-06-29 16:30 UTC (permalink / raw) To: Eric Biggers Cc: Mike Rapoport, Andrew Morton, linux-fsdevel, LKML, Linux MM, syzkaller-bugs, syzbot, Matthew Wilcox On Tue, Jun 28, 2022 at 9:41 PM Eric Biggers <ebiggers@kernel.org> wrote: > > On Tue, Jun 28, 2022 at 03:59:26PM -0700, syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. > > git tree: upstream > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 > > dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > > > > BUG: unable to handle page fault for address: ffff888021f7e005 > > #PF: supervisor write access in kernel mode > > #PF: error_code(0x0002) - not-present page > > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > > Oops: 0002 [#1] PREEMPT SMP KASAN > > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <TASK> > > zero_user_segments include/linux/highmem.h:272 [inline] > > folio_zero_range include/linux/highmem.h:428 [inline] > > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > > truncate_inode_pages mm/truncate.c:452 [inline] > > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > > simple_setattr+0xed/0x110 fs/libfs.c:535 > > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > > notify_change+0xb8c/0x12b0 fs/attr.c:424 > > do_truncate+0x13c/0x200 fs/open.c:65 > > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > RIP: 0033:0x7fb29d900899 > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > > </TASK> > > Modules linked in: > > CR2: ffff888021f7e005 > > ---[ end trace 0000000000000000 ]--- > > I think this is a bug in memfd_secret. secretmem_setattr() can race with a page > being faulted in by secretmem_fault(). Specifically, a page can be faulted in > after secretmem_setattr() has set i_size but before it zeroes out the partial > page past i_size. memfd_secret pages aren't mapped in the kernel direct map, so > the crash occurs when the kernel tries to zero out the partial page. > > I don't know what the best solution is -- maybe a rw_semaphore protecting > secretmem_fault() and secretmem_setattr()? Or perhaps secretmem_setattr() > should avoid the call to truncate_setsize() by not using simple_setattr(), given > that secretmem_setattr() only supports the size going from zero to nonzero. From my perspective the rw_semaphore approach sounds reasonable. simple_setattr() and the functions it calls to do the actual work isn't a tiny amount of code, it would be a shame to reimplement it in secretmem.c. For the rwsem, I guess the idea is setattr will take it for write, and fault will take it for read? Since setattr is a very infrequent operation - a typical use case is you'd do it exactly once right after opening the memfd_secret - this seems like it wouldn't make fault significantly less performant. It's also a pretty small change I think, just a few lines. > > The following commit tried to fix a similar bug, but it wasn't enough: > > commit f9b141f93659e09a52e28791ccbaf69c273b8e92 > Author: Axel Rasmussen <axelrasmussen@google.com> > Date: Thu Apr 14 19:13:31 2022 -0700 > > mm/secretmem: fix panic when growing a memfd_secret > > > Here's a simplified reproducer. Note, for memfd_secret to be supported, the > kernel config must contain CONFIG_SECRETMEM=y and the kernel command line must > contain secretmem.enable=1. > > #include <pthread.h> > #include <setjmp.h> > #include <signal.h> > #include <sys/mman.h> > #include <sys/syscall.h> > #include <unistd.h> > > static volatile int fd; > static jmp_buf jump_buf; > > static void *truncate_thread(void *arg) > { > for (;;) > ftruncate(fd, 1000); > } > > static void handle_sigbus(int sig) > { > longjmp(jump_buf, 1); > } > > int main(void) > { > struct sigaction act = { > .sa_handler = handle_sigbus, > .sa_flags = SA_NODEFER, > }; > pthread_t t; > void *addr; > > sigaction(SIGBUS, &act, NULL); > > pthread_create(&t, NULL, truncate_thread, NULL); > for (;;) { > fd = syscall(__NR_memfd_secret, 0); > addr = mmap(NULL, 8192, PROT_WRITE, MAP_SHARED, fd, 0); > if (setjmp(jump_buf) == 0) > *(unsigned int *)addr = 0; > munmap(addr, 8192); > close(fd); > } > } ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio 2022-06-29 16:30 ` Axel Rasmussen @ 2022-06-30 8:47 ` Mike Rapoport 2022-06-30 16:14 ` Axel Rasmussen [not found] ` <20220701073241.1277-1-hdanton@sina.com> 1 sibling, 1 reply; 7+ messages in thread From: Mike Rapoport @ 2022-06-30 8:47 UTC (permalink / raw) To: Axel Rasmussen Cc: Eric Biggers, Andrew Morton, linux-fsdevel, LKML, Linux MM, syzkaller-bugs, syzbot, Matthew Wilcox On Wed, Jun 29, 2022 at 09:30:12AM -0700, Axel Rasmussen wrote: > On Tue, Jun 28, 2022 at 9:41 PM Eric Biggers <ebiggers@kernel.org> wrote: > > > > On Tue, Jun 28, 2022 at 03:59:26PM -0700, syzbot wrote: > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. > > > git tree: upstream > > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > > > > > > BUG: unable to handle page fault for address: ffff888021f7e005 > > > #PF: supervisor write access in kernel mode > > > #PF: error_code(0x0002) - not-present page > > > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > > > Oops: 0002 [#1] PREEMPT SMP KASAN > > > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > > > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > > > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > > > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > > > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > > > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > > > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > > > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > > > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > Call Trace: > > > <TASK> > > > zero_user_segments include/linux/highmem.h:272 [inline] > > > folio_zero_range include/linux/highmem.h:428 [inline] > > > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > > > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > > > truncate_inode_pages mm/truncate.c:452 [inline] > > > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > > > simple_setattr+0xed/0x110 fs/libfs.c:535 > > > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > > > notify_change+0xb8c/0x12b0 fs/attr.c:424 > > > do_truncate+0x13c/0x200 fs/open.c:65 > > > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > > RIP: 0033:0x7fb29d900899 > > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > > > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > > > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > > > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > > > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > > > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > > > </TASK> > > > Modules linked in: > > > CR2: ffff888021f7e005 > > > ---[ end trace 0000000000000000 ]--- > > > > I think this is a bug in memfd_secret. secretmem_setattr() can race with a page > > being faulted in by secretmem_fault(). Specifically, a page can be faulted in > > after secretmem_setattr() has set i_size but before it zeroes out the partial > > page past i_size. memfd_secret pages aren't mapped in the kernel direct map, so > > the crash occurs when the kernel tries to zero out the partial page. > > > > I don't know what the best solution is -- maybe a rw_semaphore protecting > > secretmem_fault() and secretmem_setattr()? Or perhaps secretmem_setattr() > > should avoid the call to truncate_setsize() by not using simple_setattr(), given > > that secretmem_setattr() only supports the size going from zero to nonzero. > > From my perspective the rw_semaphore approach sounds reasonable. > > simple_setattr() and the functions it calls to do the actual work > isn't a tiny amount of code, it would be a shame to reimplement it in > secretmem.c. > > For the rwsem, I guess the idea is setattr will take it for write, and > fault will take it for read? Since setattr is a very infrequent > operation - a typical use case is you'd do it exactly once right after > opening the memfd_secret - this seems like it wouldn't make fault > significantly less performant. It's also a pretty small change I > think, just a few lines. Below is my take on adding a semaphore and making ->setattr() and ->fault() mutually exclusive. It's only lightly tested so I'd appreciate if Eric could give it a whirl. With addition of semaphore to secretmem_setattr() it seems we don't need special care for size changes, just calling simple_setattr() after taking the semaphore should be fine. Thoughts? From edfcb2f0d31c2132bda483635dd2a8dd295efb04 Mon Sep 17 00:00:00 2001 From: Mike Rapoport <rppt@linux.ibm.com> Date: Thu, 30 Jun 2022 11:26:37 +0300 Subject: [PATCH] secretmem: fix unhandled fault in truncate syzkaller reports the following issue: BUG: unable to handle page fault for address: ffff888021f7e005 PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> zero_user_segments include/linux/highmem.h:272 [inline] folio_zero_range include/linux/highmem.h:428 [inline] truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 truncate_inode_pages mm/truncate.c:452 [inline] truncate_pagecache+0x63/0x90 mm/truncate.c:753 simple_setattr+0xed/0x110 fs/libfs.c:535 secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 notify_change+0xb8c/0x12b0 fs/attr.c:424 do_truncate+0x13c/0x200 fs/open.c:65 do_sys_ftruncate+0x536/0x730 fs/open.c:193 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fb29d900899 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 </TASK> Modules linked in: CR2: ffff888021f7e005 ---[ end trace 0000000000000000 ]--- Eric Biggers suggested that this happens when secretmem_setattr()->simple_setattr() races with secretmem_fault() so that a page that is faulted in by secretmem_fault() (and thus removed from the direct map) is zeroed by inode truncation right afterwards. Use an rw_semaphore to make secretmem_fault() and secretmem_setattr() mutually exclusive. Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com Suggested-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> --- mm/secretmem.c | 48 ++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 40 insertions(+), 8 deletions(-) diff --git a/mm/secretmem.c b/mm/secretmem.c index 206ed6b40c1d..40573b045c96 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -47,30 +47,41 @@ bool secretmem_active(void) return !!atomic_read(&secretmem_users); } +struct secretmem_state { + struct rw_semaphore rw_sem; +}; + static vm_fault_t secretmem_fault(struct vm_fault *vmf) { struct address_space *mapping = vmf->vma->vm_file->f_mapping; struct inode *inode = file_inode(vmf->vma->vm_file); + struct secretmem_state *state = inode->i_private; pgoff_t offset = vmf->pgoff; gfp_t gfp = vmf->gfp_mask; unsigned long addr; struct page *page; + vm_fault_t ret; int err; if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) return vmf_error(-EINVAL); + down_read(&state->rw_sem); + retry: page = find_lock_page(mapping, offset); if (!page) { page = alloc_page(gfp | __GFP_ZERO); - if (!page) - return VM_FAULT_OOM; + if (!page) { + ret = VM_FAULT_OOM; + goto out; + } err = set_direct_map_invalid_noflush(page); if (err) { put_page(page); - return vmf_error(err); + ret = vmf_error(err); + goto out; } __SetPageUptodate(page); @@ -86,7 +97,8 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) if (err == -EEXIST) goto retry; - return vmf_error(err); + ret = vmf_error(err); + goto out; } addr = (unsigned long)page_address(page); @@ -94,7 +106,11 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) } vmf->page = page; - return VM_FAULT_LOCKED; + ret = VM_FAULT_LOCKED; + +out: + up_read(&state->rw_sem); + return ret; } static const struct vm_operations_struct secretmem_vm_ops = { @@ -163,11 +179,17 @@ static int secretmem_setattr(struct user_namespace *mnt_userns, { struct inode *inode = d_inode(dentry); unsigned int ia_valid = iattr->ia_valid; + struct secretmem_state *state = inode->i_private; + int ret; + down_write(&state->rw_sem); if ((ia_valid & ATTR_SIZE) && inode->i_size) - return -EINVAL; + ret = -EINVAL; + else + ret = simple_setattr(mnt_userns, dentry, iattr); + up_write(&state->rw_sem); - return simple_setattr(mnt_userns, dentry, iattr); + return ret; } static const struct inode_operations secretmem_iops = { @@ -179,22 +201,30 @@ static struct vfsmount *secretmem_mnt; static struct file *secretmem_file_create(unsigned long flags) { struct file *file = ERR_PTR(-ENOMEM); + struct secretmem_state *state; struct inode *inode; inode = alloc_anon_inode(secretmem_mnt->mnt_sb); if (IS_ERR(inode)) return ERR_CAST(inode); + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (!state) + goto err_free_inode; + file = alloc_file_pseudo(inode, secretmem_mnt, "secretmem", O_RDWR, &secretmem_fops); if (IS_ERR(file)) - goto err_free_inode; + goto err_free_state; mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); mapping_set_unevictable(inode->i_mapping); + init_rwsem(&state->rw_sem); + inode->i_op = &secretmem_iops; inode->i_mapping->a_ops = &secretmem_aops; + inode->i_private = state; /* pretend we are a normal file with zero size */ inode->i_mode |= S_IFREG; @@ -202,6 +232,8 @@ static struct file *secretmem_file_create(unsigned long flags) return file; +err_free_state: + kfree(state); err_free_inode: iput(inode); return file; base-commit: 03c765b0e3b4cb5063276b086c76f7a612856a9a -- 2.34.1 > > The following commit tried to fix a similar bug, but it wasn't enough: > > > > commit f9b141f93659e09a52e28791ccbaf69c273b8e92 > > Author: Axel Rasmussen <axelrasmussen@google.com> > > Date: Thu Apr 14 19:13:31 2022 -0700 > > > > mm/secretmem: fix panic when growing a memfd_secret > > > > > > Here's a simplified reproducer. Note, for memfd_secret to be supported, the > > kernel config must contain CONFIG_SECRETMEM=y and the kernel command line must > > contain secretmem.enable=1. > > > > #include <pthread.h> > > #include <setjmp.h> > > #include <signal.h> > > #include <sys/mman.h> > > #include <sys/syscall.h> > > #include <unistd.h> > > > > static volatile int fd; > > static jmp_buf jump_buf; > > > > static void *truncate_thread(void *arg) > > { > > for (;;) > > ftruncate(fd, 1000); > > } > > > > static void handle_sigbus(int sig) > > { > > longjmp(jump_buf, 1); > > } > > > > int main(void) > > { > > struct sigaction act = { > > .sa_handler = handle_sigbus, > > .sa_flags = SA_NODEFER, > > }; > > pthread_t t; > > void *addr; > > > > sigaction(SIGBUS, &act, NULL); > > > > pthread_create(&t, NULL, truncate_thread, NULL); > > for (;;) { > > fd = syscall(__NR_memfd_secret, 0); > > addr = mmap(NULL, 8192, PROT_WRITE, MAP_SHARED, fd, 0); > > if (setjmp(jump_buf) == 0) > > *(unsigned int *)addr = 0; > > munmap(addr, 8192); > > close(fd); > > } > > } -- Sincerely yours, Mike. ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio 2022-06-30 8:47 ` Mike Rapoport @ 2022-06-30 16:14 ` Axel Rasmussen 2022-06-30 17:04 ` Mike Rapoport 0 siblings, 1 reply; 7+ messages in thread From: Axel Rasmussen @ 2022-06-30 16:14 UTC (permalink / raw) To: Mike Rapoport Cc: Eric Biggers, Andrew Morton, linux-fsdevel, LKML, Linux MM, syzkaller-bugs, syzbot, Matthew Wilcox On Thu, Jun 30, 2022 at 1:47 AM Mike Rapoport <rppt@kernel.org> wrote: > > On Wed, Jun 29, 2022 at 09:30:12AM -0700, Axel Rasmussen wrote: > > On Tue, Jun 28, 2022 at 9:41 PM Eric Biggers <ebiggers@kernel.org> wrote: > > > > > > On Tue, Jun 28, 2022 at 03:59:26PM -0700, syzbot wrote: > > > > Hello, > > > > > > > > syzbot found the following issue on: > > > > > > > > HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. > > > > git tree: upstream > > > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 > > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 > > > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > > > > > > > > BUG: unable to handle page fault for address: ffff888021f7e005 > > > > #PF: supervisor write access in kernel mode > > > > #PF: error_code(0x0002) - not-present page > > > > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > > > > Oops: 0002 [#1] PREEMPT SMP KASAN > > > > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > > > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > > > > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > > > > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > > > > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > > > > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > > > > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > > > > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > > > > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > > > > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > > Call Trace: > > > > <TASK> > > > > zero_user_segments include/linux/highmem.h:272 [inline] > > > > folio_zero_range include/linux/highmem.h:428 [inline] > > > > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > > > > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > > > > truncate_inode_pages mm/truncate.c:452 [inline] > > > > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > > > > simple_setattr+0xed/0x110 fs/libfs.c:535 > > > > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > > > > notify_change+0xb8c/0x12b0 fs/attr.c:424 > > > > do_truncate+0x13c/0x200 fs/open.c:65 > > > > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > > > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > > > RIP: 0033:0x7fb29d900899 > > > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > > > > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > > > > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > > > > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > > > > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > > > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > > > > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > > > > </TASK> > > > > Modules linked in: > > > > CR2: ffff888021f7e005 > > > > ---[ end trace 0000000000000000 ]--- > > > > > > I think this is a bug in memfd_secret. secretmem_setattr() can race with a page > > > being faulted in by secretmem_fault(). Specifically, a page can be faulted in > > > after secretmem_setattr() has set i_size but before it zeroes out the partial > > > page past i_size. memfd_secret pages aren't mapped in the kernel direct map, so > > > the crash occurs when the kernel tries to zero out the partial page. > > > > > > I don't know what the best solution is -- maybe a rw_semaphore protecting > > > secretmem_fault() and secretmem_setattr()? Or perhaps secretmem_setattr() > > > should avoid the call to truncate_setsize() by not using simple_setattr(), given > > > that secretmem_setattr() only supports the size going from zero to nonzero. > > > > From my perspective the rw_semaphore approach sounds reasonable. > > > > simple_setattr() and the functions it calls to do the actual work > > isn't a tiny amount of code, it would be a shame to reimplement it in > > secretmem.c. > > > > For the rwsem, I guess the idea is setattr will take it for write, and > > fault will take it for read? Since setattr is a very infrequent > > operation - a typical use case is you'd do it exactly once right after > > opening the memfd_secret - this seems like it wouldn't make fault > > significantly less performant. It's also a pretty small change I > > think, just a few lines. > > Below is my take on adding a semaphore and making ->setattr() and ->fault() > mutually exclusive. It's only lightly tested so I'd appreciate if Eric > could give it a whirl. > > With addition of semaphore to secretmem_setattr() it seems we don't need > special care for size changes, just calling simple_setattr() after taking > the semaphore should be fine. Thoughts? The patch below looks correct to me. I do think we still need the check which prevents truncating a memfd_secret with an existing nonzero size, though, because I think simple_setattr's way of doing that still BUGs in a non-racy way (rwsem doesn't help with this). The patch below keeps this, so maybe I'm just misinterpreting "we don't need special care for size changes". I haven't booted+tested it, I'll leave that to Eric since he already has a reproducer setup for this. But, for what it's worth, feel free to take: Reviewed-by: Axel Rasmussen <axelrasmussen@google.com> > > From edfcb2f0d31c2132bda483635dd2a8dd295efb04 Mon Sep 17 00:00:00 2001 > From: Mike Rapoport <rppt@linux.ibm.com> > Date: Thu, 30 Jun 2022 11:26:37 +0300 > Subject: [PATCH] secretmem: fix unhandled fault in truncate > > syzkaller reports the following issue: > > BUG: unable to handle page fault for address: ffff888021f7e005 > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > Oops: 0002 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > zero_user_segments include/linux/highmem.h:272 [inline] > folio_zero_range include/linux/highmem.h:428 [inline] > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > truncate_inode_pages mm/truncate.c:452 [inline] > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > simple_setattr+0xed/0x110 fs/libfs.c:535 > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > notify_change+0xb8c/0x12b0 fs/attr.c:424 > do_truncate+0x13c/0x200 fs/open.c:65 > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > RIP: 0033:0x7fb29d900899 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > </TASK> > Modules linked in: > CR2: ffff888021f7e005 > ---[ end trace 0000000000000000 ]--- > > Eric Biggers suggested that this happens when > secretmem_setattr()->simple_setattr() races with secretmem_fault() so > that a page that is faulted in by secretmem_fault() (and thus removed > from the direct map) is zeroed by inode truncation right afterwards. > > Use an rw_semaphore to make secretmem_fault() and secretmem_setattr() > mutually exclusive. > > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > Suggested-by: Eric Biggers <ebiggers@kernel.org> > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> > --- > mm/secretmem.c | 48 ++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 40 insertions(+), 8 deletions(-) > > diff --git a/mm/secretmem.c b/mm/secretmem.c > index 206ed6b40c1d..40573b045c96 100644 > --- a/mm/secretmem.c > +++ b/mm/secretmem.c > @@ -47,30 +47,41 @@ bool secretmem_active(void) > return !!atomic_read(&secretmem_users); > } > > +struct secretmem_state { > + struct rw_semaphore rw_sem; > +}; > + > static vm_fault_t secretmem_fault(struct vm_fault *vmf) > { > struct address_space *mapping = vmf->vma->vm_file->f_mapping; > struct inode *inode = file_inode(vmf->vma->vm_file); > + struct secretmem_state *state = inode->i_private; > pgoff_t offset = vmf->pgoff; > gfp_t gfp = vmf->gfp_mask; > unsigned long addr; > struct page *page; > + vm_fault_t ret; > int err; > > if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) > return vmf_error(-EINVAL); > > + down_read(&state->rw_sem); > + > retry: > page = find_lock_page(mapping, offset); > if (!page) { > page = alloc_page(gfp | __GFP_ZERO); > - if (!page) > - return VM_FAULT_OOM; > + if (!page) { > + ret = VM_FAULT_OOM; > + goto out; > + } > > err = set_direct_map_invalid_noflush(page); > if (err) { > put_page(page); > - return vmf_error(err); > + ret = vmf_error(err); > + goto out; > } > > __SetPageUptodate(page); > @@ -86,7 +97,8 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) > if (err == -EEXIST) > goto retry; > > - return vmf_error(err); > + ret = vmf_error(err); > + goto out; > } > > addr = (unsigned long)page_address(page); > @@ -94,7 +106,11 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) > } > > vmf->page = page; > - return VM_FAULT_LOCKED; > + ret = VM_FAULT_LOCKED; > + > +out: > + up_read(&state->rw_sem); > + return ret; > } > > static const struct vm_operations_struct secretmem_vm_ops = { > @@ -163,11 +179,17 @@ static int secretmem_setattr(struct user_namespace *mnt_userns, > { > struct inode *inode = d_inode(dentry); > unsigned int ia_valid = iattr->ia_valid; > + struct secretmem_state *state = inode->i_private; > + int ret; > > + down_write(&state->rw_sem); > if ((ia_valid & ATTR_SIZE) && inode->i_size) > - return -EINVAL; > + ret = -EINVAL; > + else > + ret = simple_setattr(mnt_userns, dentry, iattr); > + up_write(&state->rw_sem); > > - return simple_setattr(mnt_userns, dentry, iattr); > + return ret; > } > > static const struct inode_operations secretmem_iops = { > @@ -179,22 +201,30 @@ static struct vfsmount *secretmem_mnt; > static struct file *secretmem_file_create(unsigned long flags) > { > struct file *file = ERR_PTR(-ENOMEM); > + struct secretmem_state *state; > struct inode *inode; > > inode = alloc_anon_inode(secretmem_mnt->mnt_sb); > if (IS_ERR(inode)) > return ERR_CAST(inode); > > + state = kzalloc(sizeof(*state), GFP_KERNEL); > + if (!state) > + goto err_free_inode; > + > file = alloc_file_pseudo(inode, secretmem_mnt, "secretmem", > O_RDWR, &secretmem_fops); > if (IS_ERR(file)) > - goto err_free_inode; > + goto err_free_state; > > mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); > mapping_set_unevictable(inode->i_mapping); > > + init_rwsem(&state->rw_sem); > + > inode->i_op = &secretmem_iops; > inode->i_mapping->a_ops = &secretmem_aops; > + inode->i_private = state; > > /* pretend we are a normal file with zero size */ > inode->i_mode |= S_IFREG; > @@ -202,6 +232,8 @@ static struct file *secretmem_file_create(unsigned long flags) > > return file; > > +err_free_state: > + kfree(state); > err_free_inode: > iput(inode); > return file; > > base-commit: 03c765b0e3b4cb5063276b086c76f7a612856a9a > -- > 2.34.1 > > > > > The following commit tried to fix a similar bug, but it wasn't enough: > > > > > > commit f9b141f93659e09a52e28791ccbaf69c273b8e92 > > > Author: Axel Rasmussen <axelrasmussen@google.com> > > > Date: Thu Apr 14 19:13:31 2022 -0700 > > > > > > mm/secretmem: fix panic when growing a memfd_secret > > > > > > > > > Here's a simplified reproducer. Note, for memfd_secret to be supported, the > > > kernel config must contain CONFIG_SECRETMEM=y and the kernel command line must > > > contain secretmem.enable=1. > > > > > > #include <pthread.h> > > > #include <setjmp.h> > > > #include <signal.h> > > > #include <sys/mman.h> > > > #include <sys/syscall.h> > > > #include <unistd.h> > > > > > > static volatile int fd; > > > static jmp_buf jump_buf; > > > > > > static void *truncate_thread(void *arg) > > > { > > > for (;;) > > > ftruncate(fd, 1000); > > > } > > > > > > static void handle_sigbus(int sig) > > > { > > > longjmp(jump_buf, 1); > > > } > > > > > > int main(void) > > > { > > > struct sigaction act = { > > > .sa_handler = handle_sigbus, > > > .sa_flags = SA_NODEFER, > > > }; > > > pthread_t t; > > > void *addr; > > > > > > sigaction(SIGBUS, &act, NULL); > > > > > > pthread_create(&t, NULL, truncate_thread, NULL); > > > for (;;) { > > > fd = syscall(__NR_memfd_secret, 0); > > > addr = mmap(NULL, 8192, PROT_WRITE, MAP_SHARED, fd, 0); > > > if (setjmp(jump_buf) == 0) > > > *(unsigned int *)addr = 0; > > > munmap(addr, 8192); > > > close(fd); > > > } > > > } > > -- > Sincerely yours, > Mike. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio 2022-06-30 16:14 ` Axel Rasmussen @ 2022-06-30 17:04 ` Mike Rapoport 0 siblings, 0 replies; 7+ messages in thread From: Mike Rapoport @ 2022-06-30 17:04 UTC (permalink / raw) To: Axel Rasmussen Cc: Eric Biggers, Andrew Morton, linux-fsdevel, LKML, Linux MM, syzkaller-bugs, syzbot, Matthew Wilcox On Thu, Jun 30, 2022 at 09:14:07AM -0700, Axel Rasmussen wrote: > On Thu, Jun 30, 2022 at 1:47 AM Mike Rapoport <rppt@kernel.org> wrote: > > On Wed, Jun 29, 2022 at 09:30:12AM -0700, Axel Rasmussen wrote: > > > On Tue, Jun 28, 2022 at 9:41 PM Eric Biggers <ebiggers@kernel.org> wrote: > > > > On Tue, Jun 28, 2022 at 03:59:26PM -0700, syzbot wrote: > > > > > Hello, > > > > > > > > > > syzbot found the following issue on: > > > > > > > > > > HEAD commit: 941e3e791269 Merge tag 'for_linus' of git://git.kernel.org.. > > > > > git tree: upstream > > > > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1670ded4080000 > > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9 > > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9bd2b7adbd34b30b87e4 > > > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=140f9ba8080000 > > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15495188080000 > > > > > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > > > Reported-by: syzbot+9bd2b7adbd34b30b87e4@syzkaller.appspotmail.com > > > > > > > > > > > > > I think this is a bug in memfd_secret. secretmem_setattr() can race with a page > > > > being faulted in by secretmem_fault(). Specifically, a page can be faulted in > > > > after secretmem_setattr() has set i_size but before it zeroes out the partial > > > > page past i_size. memfd_secret pages aren't mapped in the kernel direct map, so > > > > the crash occurs when the kernel tries to zero out the partial page. > > > > > > > > I don't know what the best solution is -- maybe a rw_semaphore protecting > > > > secretmem_fault() and secretmem_setattr()? Or perhaps secretmem_setattr() > > > > should avoid the call to truncate_setsize() by not using simple_setattr(), given > > > > that secretmem_setattr() only supports the size going from zero to nonzero. > > > > > > From my perspective the rw_semaphore approach sounds reasonable. > > > > > > simple_setattr() and the functions it calls to do the actual work > > > isn't a tiny amount of code, it would be a shame to reimplement it in > > > secretmem.c. > > > > > > For the rwsem, I guess the idea is setattr will take it for write, and > > > fault will take it for read? Since setattr is a very infrequent > > > operation - a typical use case is you'd do it exactly once right after > > > opening the memfd_secret - this seems like it wouldn't make fault > > > significantly less performant. It's also a pretty small change I > > > think, just a few lines. > > > > Below is my take on adding a semaphore and making ->setattr() and ->fault() > > mutually exclusive. It's only lightly tested so I'd appreciate if Eric > > could give it a whirl. > > > > With addition of semaphore to secretmem_setattr() it seems we don't need > > special care for size changes, just calling simple_setattr() after taking > > the semaphore should be fine. Thoughts? > > The patch below looks correct to me. I do think we still need the > check which prevents truncating a memfd_secret with an existing > nonzero size, though, because I think simple_setattr's way of doing > that still BUGs in a non-racy way (rwsem doesn't help with this). The > patch below keeps this, so maybe I'm just misinterpreting "we don't > need special care for size changes". It really was a question, because I was too lazy to dig into simple_setattr() and I know you investigated it :) > I haven't booted+tested it, I'll leave that to Eric since he already > has a reproducer setup for this. But, for what it's worth, feel free > to take: > > Reviewed-by: Axel Rasmussen <axelrasmussen@google.com> Thanks! -- Sincerely yours, Mike. ^ permalink raw reply [flat|nested] 7+ messages in thread
[parent not found: <20220701073241.1277-1-hdanton@sina.com>]
* Re: [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio [not found] ` <20220701073241.1277-1-hdanton@sina.com> @ 2022-07-07 16:46 ` Mike Rapoport 0 siblings, 0 replies; 7+ messages in thread From: Mike Rapoport @ 2022-07-07 16:46 UTC (permalink / raw) To: Hillf Danton Cc: Axel Rasmussen, Eric Biggers, Andrew Morton, linux-fsdevel, LKML, Linux MM, syzkaller-bugs, syzbot, Matthew Wilcox On Fri, Jul 01, 2022 at 03:32:41PM +0800, Hillf Danton wrote: > On Thu, 30 Jun 2022 11:47:39 +0300 Mike Rapoport wrote: > > On Wed, Jun 29, 2022 at 09:30:12AM -0700, Axel Rasmussen wrote: > > > On Tue, Jun 28, 2022 at 9:41 PM Eric Biggers <ebiggers@kernel.org> wrote: > > > > >From edfcb2f0d31c2132bda483635dd2a8dd295efb04 Mon Sep 17 00:00:00 2001 > > From: Mike Rapoport <rppt@linux.ibm.com> > > Date: Thu, 30 Jun 2022 11:26:37 +0300 > > Subject: [PATCH] secretmem: fix unhandled fault in truncate > > > > syzkaller reports the following issue: > > > > BUG: unable to handle page fault for address: ffff888021f7e005 > > PGD 11401067 P4D 11401067 PUD 11402067 PMD 21f7d063 PTE 800fffffde081060 > > Oops: 0002 [#1] PREEMPT SMP KASAN > > CPU: 0 PID: 3761 Comm: syz-executor281 Not tainted 5.19.0-rc4-syzkaller-00014-g941e3e791269 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 > > Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 > > RSP: 0018:ffffc9000329fa90 EFLAGS: 00010202 > > RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000ffb > > RDX: 0000000000000ffb RSI: 0000000000000000 RDI: ffff888021f7e005 > > RBP: ffffea000087df80 R08: 0000000000000001 R09: ffff888021f7e005 > > R10: ffffed10043efdff R11: 0000000000000000 R12: 0000000000000005 > > R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000ffb > > FS: 00007fb29d8b2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: ffff888021f7e005 CR3: 0000000026e7b000 CR4: 00000000003506f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > <TASK> > > zero_user_segments include/linux/highmem.h:272 [inline] > > folio_zero_range include/linux/highmem.h:428 [inline] > > truncate_inode_partial_folio+0x76a/0xdf0 mm/truncate.c:237 > > truncate_inode_pages_range+0x83b/0x1530 mm/truncate.c:381 > > truncate_inode_pages mm/truncate.c:452 [inline] > > truncate_pagecache+0x63/0x90 mm/truncate.c:753 > > simple_setattr+0xed/0x110 fs/libfs.c:535 > > secretmem_setattr+0xae/0xf0 mm/secretmem.c:170 > > notify_change+0xb8c/0x12b0 fs/attr.c:424 > > do_truncate+0x13c/0x200 fs/open.c:65 > > do_sys_ftruncate+0x536/0x730 fs/open.c:193 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > RIP: 0033:0x7fb29d900899 > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > > RSP: 002b:00007fb29d8b2318 EFLAGS: 00000246 ORIG_RAX: 000000000000004d > > RAX: ffffffffffffffda RBX: 00007fb29d988408 RCX: 00007fb29d900899 > > RDX: 00007fb29d900899 RSI: 0000000000000005 RDI: 0000000000000003 > > RBP: 00007fb29d988400 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb29d98840c > > R13: 00007ffca01a23bf R14: 00007fb29d8b2400 R15: 0000000000022000 > > </TASK> > > Modules linked in: > > CR2: ffff888021f7e005 > > ---[ end trace 0000000000000000 ]--- > > > > Eric Biggers suggested that this happens when > > secretmem_setattr()->simple_setattr() races with secretmem_fault() so > > that a page that is faulted in by secretmem_fault() (and thus removed > > from the direct map) is zeroed by inode truncation right afterwards. > > > > Use an rw_semaphore to make secretmem_fault() and secretmem_setattr() > > mutually exclusive. > > Given inode_lock() in do_truncate(), another simpler option is to lock > inode in the fault path if the suggested race is the root cause. Yeah, it makes sense. It does not look like a race would happen anywhere but do_truncate(). > Hillf > -- Sincerely yours, Mike. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-07-07 16:46 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2022-06-28 22:59 [syzbot] BUG: unable to handle kernel paging request in truncate_inode_partial_folio syzbot
2022-06-29 4:41 ` Eric Biggers
2022-06-29 16:30 ` Axel Rasmussen
2022-06-30 8:47 ` Mike Rapoport
2022-06-30 16:14 ` Axel Rasmussen
2022-06-30 17:04 ` Mike Rapoport
[not found] ` <20220701073241.1277-1-hdanton@sina.com>
2022-07-07 16:46 ` Mike Rapoport
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