On 10/6/22 22:36, Andrew Morton wrote: > The patch titled > Subject: lib/stackdepot.c: check if stack_table valid in __stack_depot_save > has been added to the -mm mm-nonmm-unstable branch. Its filename is > lib-check-if-stack_table-valid-in-__stack_depot_save.patch > > This patch will shortly appear at > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-check-if-stack_table-valid-in-__stack_depot_save.patch > > This patch will later appear in the mm-nonmm-unstable branch at > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next via the mm-everything > branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > and is updated there every 2-3 working days I'd suggest drop due to https://lore.kernel.org/all/b56221bd-04c7-ce23-f3e9-03cae58ec724@xxxxxxx/ > ------------------------------------------------------ > From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx> > Subject: lib/stackdepot.c: check if stack_table valid in __stack_depot_save > Date: Thu, 6 Oct 2022 09:56:31 +0800 > > NULL pointer reported in below lkp test report which should caused by > invalid stack_table in very early stage before stack_depot_early_init > called. I would like have kmemleak use stackdepot to track backtrace in > this commit which lead to stack hash access before stackdepot is > initialized. Add stack_table as extra criteria in __stack_depot_save's > entry check. > > in testcase: boot > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > [ 0.191645][ T0] BUG: kernel NULL pointer dereference, address: 0000000000000000 > [ 0.192360][ T0] #PF: supervisor read access in kernel mode > [ 0.192862][ T0] #PF: error_code(0x0000) - not-present page > [ 0.193371][ T0] PGD 0 P4D 0 > [ 0.193672][ T0] Oops: 0000 [#1] SMP PTI > [ 0.194051][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 6.0.0-rc3-00706-ga65edf711f97 #26 > [ 0.194755][ T0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 > [ 0.195583][ T0] RIP: 0010:__stack_depot_save (kbuild/src/x86_64-2/lib/stackdepot.c:452) > [ 0.196081][ T0] Code: 03 48 c7 c7 ec 17 b3 84 e8 f1 ea 85 ff 44 89 e0 23 05 d4 aa 01 03 48 8d 04 c3 48 89 c3 48 89 c7 48 89 44 24 28 e8 34 fc 85 ff <4c> 8b 33 4d 85 f6 0f 84 b6 00 00 00 8b 04 24 83 e8 01 48 8d 04 c5 > All code > ======== > 0: 03 48 c7 add -0x39(%rax),%ecx > 3: c7 (bad) > 4: ec in (%dx),%al > 5: 17 (bad) > 6: b3 84 mov $0x84,%bl > 8: e8 f1 ea 85 ff callq 0xffffffffff85eafe > d: 44 89 e0 mov %r12d,%eax > 10: 23 05 d4 aa 01 03 and 0x301aad4(%rip),%eax # 0x301aaea > 16: 48 8d 04 c3 lea (%rbx,%rax,8),%rax > 1a: 48 89 c3 mov %rax,%rbx > 1d: 48 89 c7 mov %rax,%rdi > 20: 48 89 44 24 28 mov %rax,0x28(%rsp) > 25: e8 34 fc 85 ff callq 0xffffffffff85fc5e > 2a:* 4c 8b 33 mov (%rbx),%r14 <-- trapping instruction > 2d: 4d 85 f6 test %r14,%r14 > 30: 0f 84 b6 00 00 00 je 0xec > 36: 8b 04 24 mov (%rsp),%eax > 39: 83 e8 01 sub $0x1,%eax > 3c: 48 rex.W > 3d: 8d .byte 0x8d > 3e: 04 c5 add $0xc5,%al > > Code starting with the faulting instruction > =========================================== > 0: 4c 8b 33 mov (%rbx),%r14 > 3: 4d 85 f6 test %r14,%r14 > 6: 0f 84 b6 00 00 00 je 0xc2 > c: 8b 04 24 mov (%rsp),%eax > f: 83 e8 01 sub $0x1,%eax > 12: 48 rex.W > 13: 8d .byte 0x8d > 14: 04 c5 add $0xc5,%al > [ 0.197693][ T0] RSP: 0000:ffffffff83603ca8 EFLAGS: 00010046 > [ 0.198214][ T0] RAX: ffffffff83613cd8 RBX: 0000000000000000 RCX: ffffffff81b16d2c > [ 0.198858][ T0] RDX: 0000000000000b1e RSI: 0000000000000000 RDI: 0000000000000000 > [ 0.199499][ T0] RBP: 00000000c5a6b597 R08: ffffffff8479d118 R09: 0000000000000000 > [ 0.200142][ T0] R10: 0000000000000004 R11: 0001ffffffffffff R12: 0000000027b2cd0a > [ 0.200787][ T0] R13: 0000000000000003 R14: 000000004954f68c R15: ffffffff83603d54 > [ 0.201488][ T0] FS: 0000000000000000(0000) GS:ffffffff842c9000(0000) knlGS:0000000000000000 > [ 0.202247][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.202807][ T0] CR2: 0000000000000000 CR3: 000000000360a000 CR4: 00000000000406b0 > [ 0.203470][ T0] Call Trace: > [ 0.203748][ T0] <TASK> > [ 0.203996][ T0] stack_depot_save (kbuild/src/x86_64-2/lib/stackdepot.c:534) > [ 0.204406][ T0] set_track_prepare (kbuild/src/x86_64-2/mm/slub.c:752) > [ 0.204816][ T0] ? memblock_alloc_range_nid (kbuild/src/x86_64-2/mm/memblock.c:1424) > [ 0.205311][ T0] ? memblock_alloc_internal (kbuild/src/x86_64-2/mm/memblock.c:1514) > [ 0.205781][ T0] ? memblock_alloc_try_nid (kbuild/src/x86_64-2/mm/memblock.c:1614 (discriminator 3)) > [ 0.206238][ T0] ? setup_command_line (kbuild/src/x86_64-2/init/main.c:631) > [ 0.206670][ T0] ? start_kernel (kbuild/src/x86_64-2/init/main.c:965) > [ 0.207068][ T0] ? secondary_startup_64_no_verify (kbuild/src/x86_64-2/arch/x86/kernel/head_64.S:358) > [ 0.207612][ T0] ? __raw_callee_save___native_queued_spin_unlock (??:?) > [ 0.208251][ T0] ? write_comp_data (kbuild/src/x86_64-2/kernel/kcov.c:236) > [ 0.208678][ T0] ? strncpy (kbuild/src/x86_64-2/lib/string.c:115) > [ 0.209040][ T0] __create_object (kbuild/src/x86_64-2/mm/kmemleak.c:681) > [ 0.209447][ T0] kmemleak_alloc_phys (kbuild/src/x86_64-2/mm/kmemleak.c:1212) > [ 0.209867][ T0] memblock_alloc_range_nid (kbuild/src/x86_64-2/mm/memblock.c:1424) > [ 0.210344][ T0] memblock_alloc_internal (kbuild/src/x86_64-2/mm/memblock.c:1514) > [ 0.210806][ T0] memblock_alloc_try_nid (kbuild/src/x86_64-2/mm/memblock.c:1614 (discriminator 3)) > [ 0.211255][ T0] setup_command_line (kbuild/src/x86_64-2/init/main.c:631) > [ 0.211678][ T0] start_kernel (kbuild/src/x86_64-2/init/main.c:965) > [ 0.212063][ T0] ? load_ucode_bsp (kbuild/src/x86_64-2/arch/x86/kernel/cpu/microcode/core.c:176) > [ 0.212483][ T0] secondary_startup_64_no_verify (kbuild/src/x86_64-2/arch/x86/kernel/head_64.S:358) > [ 0.212996][ T0] </TASK> > [ 0.213247][ T0] Modules linked in: > [ 0.213591][ T0] CR2: 0000000000000000 > [ 0.213955][ T0] ---[ end trace 0000000000000000 ]--- > [ 0.214415][ T0] RIP: 0010:__stack_depot_save (kbuild/src/x86_64-2/lib/stackdepot.c:452) > [ 0.214933][ T0] Code: 03 48 c7 c7 ec 17 b3 84 e8 f1 ea 85 ff 44 89 e0 23 05 d4 aa 01 03 48 8d 04 c3 48 89 c3 48 89 c7 48 89 44 24 28 e8 34 fc 85 ff <4c> 8b 33 4d 85 f6 0f 84 b6 00 00 00 8b 04 24 83 e8 01 48 8d 04 c5 > > Link: https://lkml.kernel.org/r/1665021391-1035-1-git-send-email-zhaoyang.huang@xxxxxxxxxx > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Imran Khan <imran.f.khan@xxxxxxxxxx> > Cc: ke.wang <ke.wang@xxxxxxxxxx> > Cc: Marco Elver <elver@xxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Zhaoyang Huang <huangzhaoyang@xxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > lib/stackdepot.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/lib/stackdepot.c~lib-check-if-stack_table-valid-in-__stack_depot_save > +++ a/lib/stackdepot.c > @@ -438,7 +438,7 @@ depot_stack_handle_t __stack_depot_save( > */ > nr_entries = filter_irq_stacks(entries, nr_entries); > > - if (unlikely(nr_entries == 0) || stack_depot_disable) > + if (unlikely(nr_entries == 0) || stack_depot_disable || !stack_table) > goto fast_exit; > > hash = hash_stack(entries, nr_entries); > _ > > Patches currently in -mm which might be from zhaoyang.huang@xxxxxxxxxx are > > lib-check-if-stack_table-valid-in-__stack_depot_save.patch >
