| Message ID | 20241023002558.34589-1-iii@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] linux-user: Tolerate CONFIG_LSM_MMAP_MIN_ADDR | expand |
On 10/22/24 17:24, Ilya Leoshkevich wrote: > Running qemu-i386 on a system running with SELinux in enforcing mode > (more precisely: s390x trixie container on Fedora 40) fails with: > > qemu-i386: tests/tcg/i386-linux-user/sigreturn-sigmask: Unable to find a guest_base to satisfy all guest address mapping requirements > 00000000-ffffffff > > The reason is that main() determines mmap_min_addr from > /proc/sys/vm/mmap_min_addr, but SELinux additionally defines > CONFIG_LSM_MMAP_MIN_ADDR, which is normally larger: 32K or 64K, but, > in general, can be anything. There is no portable way to query its > value: /boot/config, /proc/config and /proc/config.gz are distro- and > environment-specific. > > Once the identity map fails, the magnitude of guest_base does not > matter, so fix by starting the search from 1M or 1G. > > Closes: https://gitlab.com/qemu-project/qemu/-/issues/2598 > Suggested-by: Richard Henderson <richard.henderson@linaro.org> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > v1: https://lore.kernel.org/qemu-devel/20241021121820.483535-1-iii@linux.ibm.com/ > v1 -> v2: Start looking for a suitable hole from a higher address, > instead of falling back to probing (Richard). > > linux-user/elfload.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index 6cef8db3b53..d6ad77d27dc 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -2898,7 +2898,7 @@ static uintptr_t pgb_try_itree(const PGBAddrs *ga, uintptr_t base, > static uintptr_t pgb_find_itree(const PGBAddrs *ga, IntervalTreeRoot *root, > uintptr_t align, uintptr_t brk) > { > - uintptr_t last = mmap_min_addr; > + uintptr_t last = sizeof(uintptr_t) == 4 ? MiB : GiB; > uintptr_t base, skip; > > while (true) { Queued, thanks. r~
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 6cef8db3b53..d6ad77d27dc 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2898,7 +2898,7 @@ static uintptr_t pgb_try_itree(const PGBAddrs *ga, uintptr_t base, static uintptr_t pgb_find_itree(const PGBAddrs *ga, IntervalTreeRoot *root, uintptr_t align, uintptr_t brk) { - uintptr_t last = mmap_min_addr; + uintptr_t last = sizeof(uintptr_t) == 4 ? MiB : GiB; uintptr_t base, skip; while (true) {
Running qemu-i386 on a system running with SELinux in enforcing mode (more precisely: s390x trixie container on Fedora 40) fails with: qemu-i386: tests/tcg/i386-linux-user/sigreturn-sigmask: Unable to find a guest_base to satisfy all guest address mapping requirements 00000000-ffffffff The reason is that main() determines mmap_min_addr from /proc/sys/vm/mmap_min_addr, but SELinux additionally defines CONFIG_LSM_MMAP_MIN_ADDR, which is normally larger: 32K or 64K, but, in general, can be anything. There is no portable way to query its value: /boot/config, /proc/config and /proc/config.gz are distro- and environment-specific. Once the identity map fails, the magnitude of guest_base does not matter, so fix by starting the search from 1M or 1G. Closes: https://gitlab.com/qemu-project/qemu/-/issues/2598 Suggested-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- v1: https://lore.kernel.org/qemu-devel/20241021121820.483535-1-iii@linux.ibm.com/ v1 -> v2: Start looking for a suitable hole from a higher address, instead of falling back to probing (Richard). linux-user/elfload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)