| Message ID | PH7PR14MB559464DBDD310E755F5B21E8CEDC9@PH7PR14MB5594.namprd14.prod.outlook.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: mmap with PROT_WRITE but no PROT_READ is invalid | expand |
On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write > but not read is "Reserved for future use.". For now, they are not valid. > In the current code, -wx is marked as invalid, but -w- is not marked > as invalid. > This patch refines that judgment. > > Reported-by: xctan <xc-tan@outlook.com> > Co-developed-by: dram <dramforever@live.com> > Signed-off-by: dram <dramforever@live.com> > Co-developed-by: Ruizhe Pan <c141028@gmail.com> > Signed-off-by: Ruizhe Pan <c141028@gmail.com> > Signed-off-by: Celeste Liu <coelacanthus@outlook.com> > Cc: linux-riscv@lists.infradead.org > Cc: Palmer Dabbelt <palmer@dabbelt.com> > --- > arch/riscv/kernel/sys_riscv.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c > index 12f8a7fce78b..8a7880b9c433 100644 > --- a/arch/riscv/kernel/sys_riscv.c > +++ b/arch/riscv/kernel/sys_riscv.c > @@ -18,9 +18,8 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, > if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) > return -EINVAL; > > - if ((prot & PROT_WRITE) && (prot & PROT_EXEC)) > - if (unlikely(!(prot & PROT_READ))) > - return -EINVAL; > + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) > + return -EINVAL; > > return ksys_mmap_pgoff(addr, len, prot, flags, fd, > offset >> (PAGE_SHIFT - page_shift_offset)); Thanks, this is on for-next.
On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write > but not read is "Reserved for future use.". For now, they are not valid. > In the current code, -wx is marked as invalid, but -w- is not marked > as invalid. This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only protective page: # # There is insufficient memory for the Java Runtime Environment to continue. # Native memory allocation (mmap) failed to map 4096 bytes for failed to allocate memory for PaX check. # An error report file with more information is saved as: # /root/hs_err_pid107.log I bisected to this commit since on Linux 5.19+ java no longer works. Perhaps some fallback should be implemented, to prevent userspace breakage. It is currently documented, that at least on i386 PROT_WRITE mappings imply PROT_READ (See man mmap(2) NOTES), this would be a good place to start. Best regards, Eva
On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write > but not read is "Reserved for future use.". For now, they are not valid. > In the current code, -wx is marked as invalid, but -w- is not marked > as invalid. This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only protective page: # # There is insufficient memory for the Java Runtime Environment to continue. # Native memory allocation (mmap) failed to map 4096 bytes for failed to allocate memory for PaX check. # An error report file with more information is saved as: # /root/hs_err_pid107.log I bisected to this commit since on Linux 5.19+ java no longer works. Perhaps some fallback should be implemented, to prevent userspace breakage. It is currently documented, that at least on i386 PROT_WRITE mappings imply PROT_READ (See man mmap(2) NOTES), this would be a good place to start. Best regards, Eva
Hey Eva, On Thu, Oct 06, 2022 at 10:20:02PM +0300, Eva Kotova wrote: > On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: > > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write > > but not read is "Reserved for future use.". For now, they are not valid. > > In the current code, -wx is marked as invalid, but -w- is not marked > > as invalid. > > This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only > protective page: > > # > # There is insufficient memory for the Java Runtime Environment to continue. > # Native memory allocation (mmap) failed to map 4096 bytes for failed to > allocate memory for PaX check. > # An error report file with more information is saved as: > # /root/hs_err_pid107.log > > I bisected to this commit since on Linux 5.19+ java no longer works. > Perhaps some fallback should be implemented, to prevent userspace breakage. > It is currently documented, that at least on i386 PROT_WRITE mappings imply > PROT_READ (See man mmap(2) NOTES), this would be a good place to start. Do these patches solve your problem by any chance? https://lore.kernel.org/linux-riscv/20220915193702.2201018-1-abrestic@rivosinc.com/ I don't know the "area" at all, so it's a shot in the dark, but these both have Fixes: tags for the patch that you are blaming. Thanks, Conor.
Hey Eva, Resending as I think I may have replied to a mail with an invalid reply-to address? On Thu, Oct 06, 2022 at 10:20:02PM +0300, Eva Kotova wrote: > On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: >> As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write >> but not read is "Reserved for future use.". For now, they are not valid. >> In the current code, -wx is marked as invalid, but -w- is not marked >> as invalid. > > This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only > protective page: > > # > # There is insufficient memory for the Java Runtime Environment to continue. > # Native memory allocation (mmap) failed to map 4096 bytes for failed to > allocate memory for PaX check. > # An error report file with more information is saved as: > # /root/hs_err_pid107.log > > I bisected to this commit since on Linux 5.19+ java no longer works. > Perhaps some fallback should be implemented, to prevent userspace breakage. > It is currently documented, that at least on i386 PROT_WRITE mappings imply > PROT_READ (See man mmap(2) NOTES), this would be a good place to start. Do these patches solve your problem by any chance? https://lore.kernel.org/linux-riscv/20220915193702.2201018-1-abrestic@rivosinc.com/ I don't know the "area" at all, so it's a shot in the dark, but these both have Fixes: tags for the patch that you are blaming. Thanks, Conor.
Patch "[PATCH v4 2/2] riscv: Allow PROT_WRITE-only mmap()" applied cleanly over 5.19, fixed issues with OpenJDK. I assume this is not yet merged into linux-next, because problem persists there, hope this gets merged soon. Thanks, Eva
On Thu, Oct 06, 2022 at 10:55:00PM +0300, Eva Kotova wrote: > Patch "[PATCH v4 2/2] riscv: Allow PROT_WRITE-only mmap()" applied cleanly > over 5.19, fixed issues with OpenJDK. > > I assume this is not yet merged into linux-next, because problem persists > there, hope this gets merged soon. Yeah, not been applied yet. If you reply with a Tested-by that will help though! Would be good to also note that it breaks userspace. FYI, you've got an issue with your mail client, my msg-id from my last mail (Yz8r71PjHlpLy+kR@spud) ended up as the reply-to address for this one. The first email you sent tonight was fine though. Thanks, Conor.
On 10/6/22 21:17, Eva Kotova wrote: > On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: > > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write > > but not read is "Reserved for future use.". For now, they are not valid. > > In the current code, -wx is marked as invalid, but -w- is not marked > > as invalid. > > This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only > protective page: > > # > # There is insufficient memory for the Java Runtime Environment to > continue. > # Native memory allocation (mmap) failed to map 4096 bytes for failed to > allocate memory for PaX check. > # An error report file with more information is saved as: > # /root/hs_err_pid107.log > > I bisected to this commit since on Linux 5.19+ java no longer works. > Perhaps some fallback should be implemented, to prevent userspace > breakage. It is currently documented, that at least on i386 PROT_WRITE > mappings imply PROT_READ (See man mmap(2) NOTES), this would be a good > place to start. Which test case demonstrates the issue? Best regards Heinrich > > Best regards, > Eva > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv >
On 2022/10/11 19:23, Heinrich Schuchardt wrote: > > On 10/6/22 21:17, Eva Kotova wrote: >> On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote: >> > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write >> > but not read is "Reserved for future use.". For now, they are not >> valid. >> > In the current code, -wx is marked as invalid, but -w- is not marked >> > as invalid. >> >> This patch breaks OpenJDK/Java on RISC-V, as it tries to create a >> w-only protective page: >> >> # >> # There is insufficient memory for the Java Runtime Environment to >> continue. >> # Native memory allocation (mmap) failed to map 4096 bytes for failed >> to allocate memory for PaX check. >> # An error report file with more information is saved as: >> # /root/hs_err_pid107.log >> >> I bisected to this commit since on Linux 5.19+ java no longer works. >> Perhaps some fallback should be implemented, to prevent userspace >> breakage. It is currently documented, that at least on i386 PROT_WRITE >> mappings imply PROT_READ (See man mmap(2) NOTES), this would be a good >> place to start. > > Which test case demonstrates the issue? > > Best regards > > Heinrich > In check_pax function[1], jdk use mmap with PROT_WRITE. void* p = ::mmap(NULL, size, PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,0); [1]: https://github.com/openjdk/jdk/blob/f694f8a7671002559e7d23fdb65d5e9c768f9c03/src/hotspot/os/linux/os_linux.cpp#L4306 Best regards, Celeste
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c index 12f8a7fce78b..8a7880b9c433 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -18,9 +18,8 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len, if (unlikely(offset & (~PAGE_MASK >> page_shift_offset))) return -EINVAL; - if ((prot & PROT_WRITE) && (prot & PROT_EXEC)) - if (unlikely(!(prot & PROT_READ))) - return -EINVAL; + if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ))) + return -EINVAL; return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> (PAGE_SHIFT - page_shift_offset));